R

A layer-2 filtering technique that blocks rogue Router Advertisement messages before they reach hosts. It is meant to stop attack packets at a switch.

Plain language A layer-2 filtering technique blocking fake Router Advertisement messages.

Used in RFC 6980 RFC 7113 RFC 7610 RFC 9099

Remote Authentication Dial In User Service. A protocol in which an access device asks a central server whether a user may connect and what service to give them.

Plain language Remote Authentication Dial In User Service: a protocol asking a central server whether to allow a user.

Used in RFC 1492 RFC 2058 RFC 2059 RFC 2138 RFC 2139 RFC 2194 RFC 2477 RFC 2486 RFC 2548 RFC 2607 RFC 2618 RFC 2619 RFC 2620 RFC 2621 RFC 2809 RFC 2865 RFC 2866 RFC 2867 RFC 2868 RFC 2869 RFC 2881 RFC 2882 RFC 2888 RFC 2903 and 129 more

The Reverse Address Resolution Protocol. A host that knows only its hardware address asks a server for its IP address. Superseded in practice by BOOTP and DHCP.

Plain language Reverse Address Resolution Protocol: a host asks a server for its IP address.

Used in RFC 903 RFC 906 RFC 917 RFC 950 RFC 951 RFC 1060 RFC 1123 RFC 1201 RFC 1294 RFC 1490 RFC 1497 RFC 1700 RFC 1931 RFC 2067 RFC 2390 RFC 2427 RFC 4391 RFC 4392 RFC 7961 RFC 8171 RFC 8302

A host that keeps a table of hardware addresses and the IP addresses assigned to them, and answers RARP requests from other hosts on its network segment.

Plain language A host keeping a table of hardware addresses and their assigned IP addresses.

Used in RFC 903

Capping how many requests a client may make in a period of time. HTTP signals it with 429 Too Many Requests.

Plain language Capping how many requests a client may make in a period.

Used in RFC 998 RFC 2505 RFC 2644 RFC 2697 RFC 2813 RFC 2859 RFC 3694 RFC 3738 RFC 3871 RFC 4111 RFC 4286 RFC 4631 RFC 4657 RFC 4706 RFC 4732 RFC 5085 RFC 5158 RFC 5428 RFC 5860 RFC 5920 RFC 6192 RFC 6374 RFC 6398 RFC 6425 and 69 more

A bare public key sent in a TLS handshake instead of a full X.509 certificate, so no certificate chain or authority is involved.

Plain language A bare public key in a TLS handshake instead of a full X.509 certificate.

Used in RFC 7250 RFC 7671 RFC 7815 RFC 7924 RFC 7925 RFC 8968 RFC 9202 RFC 9641 RFC 9966

A device that implements the TRILL protocol. The terms RBridge and TRILL switch mean the same thing.

Plain language A device implementing the TRILL protocol for finding good message paths.

Used in RFC 6439 RFC 6905 RFC 7067 RFC 7172 RFC 7174 RFC 7175 RFC 7176 RFC 7177 RFC 7179 RFC 7357 RFC 7455 RFC 7780 RFC 7781 RFC 7782 RFC 7783 RFC 7956 RFC 7968 RFC 7978 RFC 8139 RFC 8171 RFC 8302 RFC 8361 RFC 8380 RFC 8383 and 4 more

A TRILL facility for carrying control messages between RBridges as TRILL Data packets. Each kind of message has a protocol number in an IANA registry.

Plain language A TRILL facility for control messages between RBridges as TRILL Data packets.

Used in RFC 7178 RFC 7179 RFC 7978 RFC 8139 RFC 8381 RFC 8564

A secret-key block cipher with a 64-bit block and a key of 1 to 128 bytes, designed for fast implementation on 16-bit microprocessors. It was described by Ron Rivest in RFC 2268.

Plain language A cipher that scrambles data in 64-bit blocks with a secret key, and that was built to run quickly on small computers.

Used in RFC 2268 RFC 3217

The response code field in a DNS message header. It reports whether the query succeeded, for example NOERROR or Name Error (NXDOMAIN).

Plain language The response code field in a DNS header reporting success or failure.

Used in RFC 1035 RFC 2136 RFC 2308 RFC 2671 RFC 2845 RFC 4074 RFC 4408 RFC 5395 RFC 6672 RFC 6891 RFC 6895 RFC 8005 RFC 8490 RFC 8765 RFC 8906 RFC 8914 RFC 8945 RFC 9499 RFC 9619 RFC 9664 RFC 9665 RFC 10029

The Registration Data Access Protocol, an HTTP-based protocol that returns registration data as JSON objects.

Plain language Registration Data Access Protocol: an HTTP-based protocol returning registration data as JSON.

Used in RFC 7480 RFC 7481 RFC 7484 RFC 7485 RFC 8056 RFC 8521 RFC 8605 RFC 8977 RFC 8982 RFC 9082 RFC 9083 RFC 9536 RFC 9537 RFC 9560 RFC 9910

Remote Direct Memory Access, a technique for moving data efficiently between computers by having network hardware place it directly into destination buffers in memory.

Plain language Remote Direct Memory Access: a technique for moving data directly into destination memory.

Used in RFC 4297 RFC 5040 RFC 5043 RFC 5044 RFC 5046 RFC 5047 RFC 6581 RFC 7145 RFC 7306 RFC 7609 RFC 8166 RFC 8167

Text that is transmitted instantly as it is typed or created, so recipients can read a message while it is still being written.

Plain language Text transmitted instantly as it is typed so recipients see the message being written.

Used in RFC 4103 RFC 5194 RFC 9071

A Kerberos administrative domain with its own KDC and principal database. Realm names conventionally look like an upper-case DNS name such as EXAMPLE.COM.

Plain language A Kerberos administrative domain with its own KDC and principal database.

Used in RFC 1510 RFC 1731 RFC 1964 RFC 2069 RFC 2101 RFC 2194 RFC 2486 RFC 2607 RFC 2617 RFC 2663 RFC 2712 RFC 2809 RFC 2865 RFC 3102 RFC 3103 RFC 3104 RFC 3235 RFC 3579 RFC 3588 RFC 3846 RFC 4004 RFC 4120 RFC 4282 RFC 4284 and 39 more

Storage space in an IMP used to hold packets of a multi-packet message until all packets arrive and the complete message is reassembled.

Plain language Storage space holding packet fragments until a complete message arrives.

Used in RFC 626 RFC 815 RFC 2682 RFC 4623

The 16-bit Window field a TCP endpoint advertises to say how many more bytes it is currently willing to accept, which limits how much the peer may send at once.

Plain language The TCP field advertising how many more bytes a receiver is willing to accept.

Used in RFC 793 RFC 1323 RFC 2406 RFC 2488 RFC 2581 RFC 3150 RFC 3481 RFC 3649 RFC 4953 RFC 5681 RFC 5961 RFC 6349 RFC 6429 RFC 6479 RFC 6675 RFC 6928 RFC 7323 RFC 8684 RFC 9293 RFC 9467 RFC 9687 RFC 9840

A compact summary of recent stream history included in each RTP MIDI packet. After a packet loss, the receiver uses it to repair errors without asking for retransmission.

Plain language A summary of recent stream history in RTP MIDI packets for error repair.

Used in RFC 4695 RFC 4696 RFC 6295

A DNS server that answers a client's question by looking up the answer on its behalf, often caching results. DoH mainly covers the link between a client and one of these.

Plain language A DNS server that looks up answers on behalf of clients.

Used in RFC 1034 RFC 1536 RFC 2308 RFC 2870 RFC 3225 RFC 3646 RFC 3655 RFC 3755 RFC 3833 RFC 4035 RFC 4074 RFC 4339 RFC 4697 RFC 4986 RFC 5001 RFC 5222 RFC 5358 RFC 5452 RFC 5625 RFC 6106 RFC 6147 RFC 6303 RFC 6672 RFC 6731 and 42 more

A router technique that drops packets at random as a queue fills, to signal congestion early. RFC 2549 plays on the acronym: packets MAY be marked for deletion using RED paint.

Plain language A router technique dropping packets at random as a queue fills to signal congestion.

Used in RFC 2309 RFC 2549 RFC 2597 RFC 2638 RFC 3150 RFC 3168 RFC 5562 RFC 6817 RFC 7141 RFC 7567 RFC 8033 RFC 8257

A set of Provider Edge devices that use ICCP to act together as a single unit for high availability.

Plain language A set of Provider Edge devices acting together as a single unit.

Used in RFC 7121 RFC 7275 RFC 7727

An extra, usually lower-bandwidth copy of data sent alongside later data, so that the original can be rebuilt if its own packet is lost.

Plain language An extra lower-bandwidth copy of data sent to allow rebuilding if packets are lost.

Used in RFC 2198 RFC 4102 RFC 4103 RFC 4734 RFC 8854

A SIP request that asks the receiving user agent to send a request to a third party named in the Refer-To header. It is used for things like call transfer.

Used in RFC 4508 RFC 5359 RFC 5368

The identifier a client expects to find in a server's certificate. The client builds it from the source domain and, optionally, an application service type, independently of what the server presents.

Used in RFC 6125 RFC 9525

A reply that tells a client to take its query to another server that may hold the answer, instead of answering it directly.

Plain language A reply telling a client to ask another server instead of answering directly.

Used in RFC 1714 RFC 1913 RFC 1914 RFC 2167 RFC 2251 RFC 2651 RFC 2654 RFC 2968 RFC 2969 RFC 4516 RFC 5661 RFC 5716 RFC 7532 RFC 8111 RFC 9499

A denial of service attack in which the attacker sends packets with the victim's address as the source to innocent nodes. Their replies then flood the victim and hide where the attack began.

Plain language A denial of service attack sending packets with the victim's address to innocent nodes.

Used in RFC 3964 RFC 4948 RFC 4993 RFC 7664

The IP address and port that identify a client as seen by another host, typically a STUN server. When a NAT sits in between, it is the public address the NAT allocated to the client.

Plain language The IP address and port identifying a client as seen by another host.

Used in RFC 5389 RFC 8489

A credential used to obtain a new access token when the current one expires or is no longer valid. It is issued with the access token and is only ever sent to the authorization server.

Plain language A credential obtaining a new access token when the current one expires.

Used in RFC 6749 RFC 6819 RFC 7009 RFC 7628 RFC 7662 RFC 8252 RFC 8628 RFC 8693 RFC 8705 RFC 8898 RFC 8936 RFC 9396 RFC 9449 RFC 9560 RFC 9700 RFC 10017 RFC 10027

One of the organizations, such as RIPE NCC, that receive blocks of IP address space from IANA and allocate them to providers and sites in their region.

Plain language An organization receiving IP blocks from IANA and allocating them regionally.

Used in RFC 1366 RFC 1466 RFC 1591 RFC 1879 RFC 1881 RFC 2008 RFC 2050 RFC 2517 RFC 2650 RFC 2725 RFC 2901 RFC 2928 RFC 3152 RFC 3587 RFC 3701 RFC 3707 RFC 3732 RFC 3779 RFC 3981 RFC 4012 RFC 4116 RFC 4632 RFC 4698 RFC 4773 and 29 more

A service provider that represents clients in registering and managing objects, such as domain names, in a registry.

Plain language A service provider representing clients in registering objects like domain names.

Used in RFC 819 RFC 2146 RFC 2832 RFC 3375 RFC 3764 RFC 3915 RFC 4725 RFC 4930 RFC 5922 RFC 6461 RFC 7877 RFC 8003 RFC 8396 RFC 9154

A party that checks a subject's identity and details on behalf of a Certification Authority before a certificate is issued.

Plain language A party checking a subject's identity on behalf of a Certification Authority.

Used in RFC 2459 RFC 2510 RFC 2585 RFC 4210 RFC 4211 RFC 4683 RFC 5272 RFC 5273 RFC 5274 RFC 7030 RFC 9483 RFC 9733 RFC 9810 RFC 9811 RFC 10002 RFC 10004

The ROVR is a value carried in registrations that identifies who registered an address. In this RFC it also identifies the origin of an anycast or multicast advertisement.

Plain language A value identifying who registered an address in registration and advertisement.

Used in RFC 8505 RFC 9010 RFC 9685 RFC 9926

The rule that controls how new assignments in a registry are accepted, such as First Come First Served, Expert Review or Standards Action. RFC 8126 defines ten well-known ones.

Plain language The rule controlling how new registry assignments are accepted.

Used in RFC 4250 RFC 8126

A named group of media type subtypes, such as the standards, vendor or personal tree, that has its own naming prefix and its own approval requirements.

Plain language A named group of media type subtypes with its own naming prefix and approval rules.

Used in RFC 2048 RFC 4288 RFC 6838

The authoritative database that stores all domain names and name servers for a Top Level Domain, operated by a registry operator.

Plain language The authoritative database storing all domain names and name servers for a TLD.

Used in RFC 1340 RFC 2146 RFC 2832 RFC 3375 RFC 4408 RFC 4646 RFC 4725 RFC 4930 RFC 5226 RFC 6461 RFC 7116 RFC 7484 RFC 7500 RFC 8137

Running a new key exchange on a live connection so that fresh encryption keys replace the old ones. Limiting how much data one key protects reduces what an attacker can learn from it.

Plain language Running a new key exchange to replace encryption keys on a live connection.

Used in RFC 2093 RFC 4344 RFC 8645

A single attribute and value that identifies an entry relative to its parent in the directory tree, for example cn=John Smith.

Plain language Relative Distinguished Name: a single attribute identifying an entry in a directory tree.

Used in RFC 1384 RFC 1564 RFC 4514

One component of a distinguished name. It is made of one or more attribute type and value pairs that identify an entry among its siblings.

Plain language One component of a distinguished name identifying an entry among siblings.

Used in RFC 1255 RFC 1617 RFC 2253 RFC 2849 RFC 4514

An XML schema language that describes the allowed structure and contents of XML documents. It is Part 2 of the ISO/IEC DSDL family of standards.

Plain language An XML schema language describing allowed structure and contents of XML documents.

Used in RFC 4911 RFC 6110 RFC 6351 RFC 6501 RFC 6739 RFC 7991 RFC 9718

A gateway or other host on the client's network that forwards broadcast BOOTP requests to a server on another network. It writes its own address into the giaddr field so the reply can find its way back.

Plain language A gateway forwarding broadcast BOOTP requests to a server on another network.

Used in RFC 951 RFC 1532 RFC 1541 RFC 1542 RFC 2131 RFC 3011 RFC 3046 RFC 3074 RFC 3118 RFC 3256 RFC 3315 RFC 3456 RFC 3527 RFC 3588 RFC 3993 RFC 4014 RFC 4030 RFC 4039 RFC 4243 RFC 4388 RFC 4580 RFC 4649 RFC 4994 RFC 5007 and 49 more

An X.400 Message Transfer Agent that serves as a routing point between MHS domains, often supporting multiple network protocol stacks to bridge domains that use different technologies.

Plain language An X.400 Message Transfer Agent serving as a routing point between domains.

Used in RFC 1465 RFC 1649

REsource LOcation And Discovery, a peer-to-peer signaling protocol used to maintain an overlay network and to store data in and retrieve data from the overlay.

Plain language REsource LOcation And Discovery: a peer-to-peer protocol maintaining an overlay network.

Used in RFC 7086 RFC 7374

A system that accepts identity information from an identity provider in order to sign a user in.

Plain language A system accepting identity information from an identity provider.

Used in RFC 4683 RFC 6024 RFC 6480 RFC 6487 RFC 6489 RFC 6595 RFC 7115 RFC 7132 RFC 7831 RFC 7833 RFC 8176 RFC 8182 RFC 8416 RFC 8473 RFC 8630 RFC 8659 RFC 8897 RFC 9286 RFC 9399 RFC 9455 RFC 9560 RFC 9589 RFC 9691 RFC 9829

A procedure in which one system produces believable information about its own state so a remote party can decide whether to trust it. In RATS the information is called Evidence.

Plain language A procedure where a system produces believable information about its state so a remote party can decide whether to trust it.

Used in RFC 9334 RFC 9576

A process in which a device, the attester, produces signed evidence about its own state so that another party can decide whether to trust it.

Plain language A process where a device produces signed evidence about its state.

Used in RFC 9683 RFC 9711 RFC 9782 RFC 9999 RFC 10013

A network service that lets users submit batch computing jobs to a distant computer and retrieve results, commonly abbreviated RJE.

Plain language A network service letting users submit batch jobs to a distant computer.

Used in RFC 88 RFC 324 RFC 477 RFC 551 RFC 599 RFC 725

A protocol that lets a program call a function or routine that runs on another computer over the network, as if it were a local function call.

Plain language A protocol letting a program call a function running on another computer.

Used in RFC 955 RFC 1045 RFC 1050 RFC 1057 RFC 1094 RFC 1813 RFC 2188 RFC 5403 RFC 5531 RFC 7530 RFC 7863 RFC 7950 RFC 8166 RFC 8167

A well-known place where hosts behind a NAT or firewall register an address and port, so that peers can contact them.

Plain language A well-known place where hidden hosts register so peers can contact them.

Used in RFC 2117 RFC 2189 RFC 2201 RFC 2362 RFC 2934 RFC 3446 RFC 3618 RFC 3956 RFC 3973 RFC 4601 RFC 4608 RFC 4609 RFC 4610 RFC 5015 RFC 5059 RFC 5110 RFC 5207 RFC 5240 RFC 6226 RFC 6308 RFC 6513 RFC 6826 RFC 7438 RFC 7442 and 10 more

A server that relays incoming connection requests to a mobile host at its current location, maintaining reachability while the host's IP address changes.

Plain language A server relaying connection requests to a mobile host at its current location.

Used in RFC 5128 RFC 5205 RFC 7393 RFC 8003 RFC 8004 RFC 8005 RFC 8046

Changing the IP addresses of hosts and networks. RFC 1918 notes that moving a host between private and public use, or merging two private internets, can require it, along with DNS and configuration changes.

Plain language Changing the IP addresses of hosts and networks.

Used in RFC 1627 RFC 1787 RFC 1900 RFC 1918 RFC 2008 RFC 2050 RFC 2071 RFC 2072 RFC 2101 RFC 2260 RFC 2462 RFC 2874 RFC 2894 RFC 3177 RFC 3178 RFC 3194 RFC 3364 RFC 4085 RFC 4116 RFC 4193 RFC 4242 RFC 4984 RFC 5220 RFC 5375 and 13 more

The process of replicating a packet to multiple destinations and encapsulating each copy into a separate tunnel.

Plain language Replicating a packet to multiple destinations and encapsulating each copy.

Used in RFC 8350 RFC 8378

A media flow consisting of repair packets generated by FEC encoding that can be used to recover missing or corrupted source packets.

Plain language A media flow of repair packets generated by FEC encoding.

Used in RFC 5956 RFC 6364 RFC 6695 RFC 9223

The time spanned by a FEC block, covering its source packets and the matching repair packets. A receiver waits at least this long before declaring a decoding failure.

Plain language The time span of a FEC block covering source and repair packets.

Used in RFC 6364 RFC 8627

The SIP Replaces header field, defined in RFC 3891. It carries the identity of an existing session, so that a new INVITE can take that session over instead of starting a second one beside it.

Plain language A header field that names the session a new invitation should take over, so that two calls do not compete.

Used in RFC 5359 RFC 5631

An attack in which a recorded message is sent again to make the receiver act on it twice. 0-RTT data in TLS is exposed to this.

Plain language An attack sending a recorded message again to make the receiver act twice.

Used in RFC 1057 RFC 1135 RFC 1334 RFC 1507 RFC 1704 RFC 1760 RFC 1938 RFC 1994 RFC 2025 RFC 2085 RFC 2136 RFC 2203 RFC 2243 RFC 2274 RFC 2289 RFC 2419 RFC 2420 RFC 2444 RFC 2571 RFC 2574 RFC 2617 RFC 2712 RFC 2747 RFC 2750 and 197 more

A server's record of recently seen authenticators, used to reject a copy of an earlier request that an attacker captured and resent within the clock-skew window.

Plain language A server's record of recently seen authenticators to reject old requests.

Used in RFC 4120 RFC 5661 RFC 8881

A defense against an attacker who records valid packets and sends them again later. SRTP rejects packets whose index has already been seen.

Plain language A defense against resending valid packets recorded earlier.

Used in RFC 1460 RFC 1507 RFC 1725 RFC 1910 RFC 1961 RFC 1964 RFC 2002 RFC 2006 RFC 2082 RFC 2085 RFC 2195 RFC 2203 RFC 2274 RFC 2385 RFC 2401 RFC 2402 RFC 2406 RFC 2574 RFC 2743 RFC 2744 RFC 2748 RFC 2779 RFC 2894 RFC 3012 and 128 more

Creating and maintaining a duplicate copy of a data set on a different server. Copies are kept by schedule, on demand, or by synchronized strategies.

Used in RFC 1913 RFC 2887 RFC 3040 RFC 5716

A Segment Routing segment that tells a node to copy an incoming packet and send the copies to a set of downstream nodes. Chains of them can form a multicast-style tree.

Plain language A Segment Routing segment instructing a node to copy and forward packets.

Used in RFC 9524 RFC 9960

The ROID, an identifier assigned to an object in the registry when it was created. Domain and host records in a deposit carry their ROID.

Plain language A unique identifier assigned to an object when created in the registry.

Used in RFC 4933 RFC 6480 RFC 9022

A unique identifier assigned by the registry server to each object (domain, host, contact) when it is created. The ROID persists for the lifetime of the object even if other attributes change.

Used in RFC 4931 RFC 7275

Information that reflects the state of a resource, together with metadata such as its media type, in a form that can be sent in an HTTP message. One resource can have several representations, for example HTML and JSON.

Plain language Information reflecting a resource's state in a form that can be sent in HTTP.

Used in RFC 1003 RFC 1014 RFC 4506 RFC 7231 RFC 7959 RFC 8132 RFC 8144 RFC 9110 RFC 9530 RFC 9695

A single independent JSON object holding reputation information about one subject. A reputation query returns one or more of them.

Plain language A single JSON object holding reputation information about one subject.

Used in RFC 7070 RFC 7071 RFC 7073

A document published by the IETF describing Internet standards, technologies, and procedures.

Plain language Request for Comments: documents describing Internet standards and procedures.

Used in RFC 160 RFC 170 RFC 800 RFC 1175 RFC 1392 RFC 1396 RFC 2223 RFC 2346 RFC 3933 RFC 3978 RFC 4844 RFC 5385 RFC 6722 RFC 7322 RFC 7841 RFC 8700 RFC 9389

A JSON Web Token that carries the parameters of an OAuth authorization request as claims. It can be signed and optionally encrypted.

Plain language A JSON Web Token carrying OAuth authorization request parameters.

Used in RFC 9101 RFC 9126

An attack that exploits two HTTP recipients, such as a proxy and a server, disagreeing about where a request ends, so a hidden second request slips past checks.

Plain language An attack exploiting disagreement about where a request ends in HTTP.

Used in RFC 7230 RFC 9112 RFC 9931

The part of an HTTP request line, after the method, that says what the request is for. It takes one of four forms: origin, absolute, authority or asterisk.

Plain language The part of an HTTP request line specifying what the request is for.

Used in RFC 2976 RFC 7230 RFC 9112 RFC 10008

A reference value that stands in for an authorization request stored at the authorization server. The client presents it at the authorization endpoint instead of repeating all the request parameters.

Used in RFC 5806 RFC 7044 RFC 7544 RFC 9126

The first line of an HTTP/1.0 full request: a method, the Request-URI and the HTTP version, separated by spaces and ended by CRLF, for example GET /index.html HTTP/1.0.

Plain language The first line of an HTTP request showing the method, URI and version.

Used in RFC 1945 RFC 3875 RFC 7230 RFC 7231

The activity of directing a content request from a user agent to a suitable surrogate, typically based on network conditions, load, and geographic proximity.

Plain language Directing a content request from a user to a suitable server.

Used in RFC 3466 RFC 3568 RFC 8804

One of the capitalized words RFC 2119 defines to state how strongly a rule applies: MUST, MUST NOT, SHOULD, SHOULD NOT and MAY, with synonyms such as REQUIRED, SHALL, RECOMMENDED and OPTIONAL.

Plain language Capitalized words such as MUST or SHOULD defining requirement strength.

Used in RFC 1100 RFC 1140 RFC 1540 RFC 2119 RFC 2193 RFC 2223 RFC 2251 RFC 2281 RFC 2306 RFC 2356 RFC 2360 RFC 2379 RFC 2389 RFC 2394 RFC 2505 RFC 2566 RFC 2609 RFC 2681 RFC 2750 RFC 2784 RFC 2846 RFC 2857 RFC 2911 RFC 2984 and 163 more

The specification of how important it is for a system to implement a protocol, categorized as required, recommended, elective, limited use, or not recommended.

Plain language The importance specification for implementing a protocol.

Used in RFC 1250 RFC 1800 RFC 2300 RFC 2988 RFC 3066 RFC 4564

A group in the IRTF that explores long-term research questions and ideas, with no requirement to produce standards or reach consensus.

Plain language A group in the IRTF exploring long-term research questions.

Used in RFC 4440 RFC 7418 RFC 7827

A DNS client or server component that looks up names on behalf of programs; stub resolvers ask recursive resolvers, which ask authoritative servers.

Plain language A DNS client or server component looking up names on behalf of programs.

Used in RFC 819 RFC 881 RFC 882 RFC 883 RFC 921 RFC 974 RFC 1031 RFC 1032 RFC 1033 RFC 1034 RFC 1118 RFC 1178 RFC 1535 RFC 1536 RFC 1612 RFC 1737 RFC 2168 RFC 2182 RFC 2276 RFC 2535 RFC 2539 RFC 2672 RFC 2826 RFC 3008 and 52 more

In HTTP, the target of a request: anything that can be identified by a URI, such as a document, an image, a collection or a service. A resource is distinct from the representations that are sent for it.

Plain language In HTTP, the target of a request such as a document or service.

Used in RFC 268 RFC 274 RFC 276 RFC 286 RFC 518 RFC 1152 RFC 2291 RFC 2413 RFC 3253 RFC 3334 RFC 3532 RFC 4195 RFC 4198 RFC 4463 RFC 4662 RFC 5013 RFC 5023 RFC 5279 RFC 5362 RFC 5689 RFC 6288 RFC 6289 RFC 6903 RFC 7396 and 6 more

The final step of client stream negotiation in which the client is given a resourcepart, producing a full JID that identifies this particular connection of the account.

Plain language The final step in client stream negotiation producing a full unique identifier.

Used in RFC 471 RFC 3920 RFC 6120

A SIP server that subscribes to a set of resources on behalf of a client and reports changes in their state through a single subscription dialog.

Plain language A SIP server subscribing to resources on behalf of a client.

Used in RFC 4660 RFC 4662 RFC 4826 RFC 5367

In OAuth, an entity able to grant access to a protected resource. When it is a person, it is called the end-user.

Plain language In OAuth, an entity able to grant access to a protected resource.

Used in RFC 2819 RFC 5849 RFC 6749 RFC 7009 RFC 7523 RFC 7635 RFC 7662 RFC 9068 RFC 9200 RFC 9396 RFC 9635 RFC 9700 RFC 9767

A system for authenticating Internet number resource information using digital certificates, used primarily to secure routing information.

Plain language Digital certificates proving network address ownership and announcement authorization.

Used in RFC 6480 RFC 6481 RFC 6482 RFC 6487 RFC 6489 RFC 6492 RFC 6493 RFC 6810 RFC 6811 RFC 6945 RFC 7115 RFC 7132 RFC 7754 RFC 8182 RFC 8205 RFC 8207 RFC 8209 RFC 8210 RFC 8211 RFC 8360 RFC 8416 RFC 8488 RFC 8635 RFC 9255 and 7 more

The basic unit of DNS data. Each record has a name, type, class, time to live, and type-specific data (RDATA).

Plain language The basic unit of DNS data with a name, type, class, TTL and type-specific data.

Used in RFC 882 RFC 883 RFC 974 RFC 1033 RFC 1035 RFC 1183 RFC 1279 RFC 1348 RFC 1480 RFC 1530 RFC 1664 RFC 1703 RFC 1706 RFC 1712 RFC 1794 RFC 1876 RFC 1886 RFC 1912 RFC 1995 RFC 1996 RFC 2065 RFC 2136 RFC 2163 RFC 2168 and 103 more

The server that holds the protected data or functions in OAuth. It checks the access token on each request and answers or refuses.

Plain language The server holding protected data in OAuth.

Used in RFC 6749 RFC 6750 RFC 6819 RFC 7635 RFC 7662 RFC 8705 RFC 8707 RFC 9068 RFC 9200 RFC 9201 RFC 9202 RFC 9203 RFC 9396 RFC 9430 RFC 9431 RFC 9449 RFC 9470 RFC 9594 RFC 9635 RFC 9700 RFC 9701 RFC 9728 RFC 9767 RFC 9770 and 1 more

A system that combines metadata attached to a resource with an agent program that automatically notifies resource location systems when the resource moves or changes.

Plain language A system combining metadata with an agent notifying about resource changes.

Used in RFC 1727 RFC 1728

A defined group of assertions and extra metadata that a reputation service provider can include in a reply for a given reputation application.

Plain language A defined group of assertions a reputation service may include in a reply.

Used in RFC 7070 RFC 7073

An attack, also called CRLF injection, in which an attacker gets carriage-return and line-feed characters into a response header so that one response looks like two.

Plain language An attack injecting line breaks into response headers to create two responses.

Used in RFC 9112

Representational State Transfer, an architectural style where resources have web addresses and servers keep no client session state. Clients move between states by following links.

Plain language Representational State Transfer: an architectural style where resources have addresses.

Used in RFC 5789 RFC 7285 RFC 8322

A REST-based variant of NETCONF that uses HTTP methods and is lighter-weight than NETCONF, defined in RFC 8040.

Plain language A REST-based variant of NETCONF using HTTP methods.

Used in RFC 7951 RFC 7952 RFC 8071 RFC 8072 RFC 8177 RFC 8242 RFC 8341 RFC 8344 RFC 8407 RFC 8572 RFC 8650 RFC 8783 RFC 8795 RFC 9127 RFC 9129 RFC 9232 RFC 9243 RFC 9314 RFC 9363 RFC 9640 RFC 9641 RFC 9642 RFC 9645 RFC 9731 and 1 more

Changing the intended destination of a call or request while it is being routed, for example when a call is forwarded to another number.

Plain language Changing the destination of a call or request while it is being routed.

Used in RFC 3311 RFC 5479 RFC 7044 RFC 8946

Sending a segment again because no acknowledgment for it came back before a timer expired. TCP keeps a copy on a retransmission queue until the data is acknowledged.

Plain language Sending a segment again because no acknowledgment arrived.

Used in RFC 65 RFC 68 RFC 71 RFC 442 RFC 516 RFC 635 RFC 675 RFC 700 RFC 793 RFC 889 RFC 896 RFC 905 RFC 907 RFC 908 RFC 916 RFC 938 RFC 964 RFC 998 RFC 1002 RFC 1008 RFC 1016 RFC 1045 RFC 1094 RFC 1323 and 121 more

The time interval a sender waits without receiving an acknowledgment before assuming the data was lost and resending it.

Plain language The time interval a sender waits before resending data assumed lost.

Used in RFC 889 RFC 1323 RFC 2883 RFC 2988 RFC 3042 RFC 5562 RFC 5682 RFC 6298 RFC 6582 RFC 6675 RFC 7661 RFC 7765

An HTTP header that tells a client how long to wait before trying again, as a number of seconds or as a date. RFC 6585 allows it on 429 responses.

Plain language An HTTP header telling a client how long to wait before trying again.

Used in RFC 5390 RFC 6585 RFC 7339 RFC 7480 RFC 7481 RFC 8030 RFC 9457

A check that a node can actually receive packets sent to a claimed address, by sending it a secret token and requiring that the token be used in the reply.

Plain language A check that a node can receive packets at a claimed address.

Used in RFC 3775 RFC 4225 RFC 4651 RFC 4889 RFC 6521

A test in which a receiver sends a challenge to a claimed address and accepts the address only if the reply proves the peer can be reached there.

Plain language A test sending a challenge to verify a peer can be reached at a claimed address.

Used in RFC 4555 RFC 9853

A DNS lookup that finds the hostname associated with an IP address, performed by querying IN-ADDR.ARPA zones with the address octets reversed.

Plain language A DNS lookup finding the hostname for an IP address.

Used in RFC 1383 RFC 1912 RFC 2163 RFC 2317 RFC 4472 RFC 4702 RFC 5158 RFC 5451 RFC 6177 RFC 6305 RFC 6449 RFC 6535 RFC 7534 RFC 7793 RFC 8244 RFC 8368 RFC 8686 RFC 8777

A DNS query that starts from an address and looks for the host name. For IPv6 it uses a name built under the IP6.ARPA domain.

Plain language A DNS query starting from an address and finding the hostname.

Used in RFC 3596 RFC 7534

A check that accepts a multi-destination packet only if it arrives on the port where it is expected to arrive. Packets on any other port are dropped.

Plain language A check accepting packets only on the port where they are expected.

Used in RFC 922 RFC 1716 RFC 3704 RFC 3973 RFC 5015 RFC 5132 RFC 5374 RFC 5496 RFC 5635 RFC 5757 RFC 6037 RFC 6754 RFC 6831 RFC 6959 RFC 7761 RFC 7891 RFC 8243 RFC 8279 RFC 8361 RFC 8487 RFC 9466 RFC 9856

A proxy that sits in front of one or more servers and receives requests on their behalf. Clients see the proxy rather than the servers behind it.

Used in RFC 6202 RFC 7239

In Mobile IP, a tunnel that starts at the mobile node's care-of address and ends at the home agent, carrying the node's outgoing packets back toward its home network.

Plain language A tunnel carrying outgoing packets back toward the home network.

Used in RFC 2344 RFC 3024 RFC 5177 RFC 5944

The function that edits and publishes documents in the RFC series.

Plain language The function editing and publishing documents in the RFC series.

Used in RFC 72 RFC 825 RFC 1111 RFC 1160 RFC 1199 RFC 1280 RFC 1311 RFC 1358 RFC 1500 RFC 1543 RFC 1594 RFC 1600 RFC 1602 RFC 1603 RFC 1720 RFC 1899 RFC 2014 RFC 2026 RFC 2028 RFC 2223 RFC 2399 RFC 2418 RFC 2441 RFC 2468 and 62 more

Ready For Next Message, the reply an ARPANET destination IMP sends to say a message arrived and the source may send another.

Plain language Ready For Next Message: the reply confirming a message arrived.

Used in RFC 68 RFC 442 RFC 527 RFC 626 RFC 632 RFC 878

The Routing Information Protocol, a distance-vector routing protocol that measures distance in hops, the number of gateways a packet has to cross. A hop count of 16 means the link is down, so hosts more than 15 gateways apart cannot communicate over it.

Plain language A routing protocol that measures distance by counting the routers a packet has to pass through.

Used in RFC 1118 RFC 1723 RFC 1724

Remote Network Monitoring: a standard framework for network management agents to observe and report on traffic characteristics on network links.

Plain language Remote Network Monitoring: a framework for agents observing traffic characteristics.

Used in RFC 1513 RFC 3273 RFC 3395 RFC 3577 RFC 3919 RFC 4710

A remote monitoring agent, implemented as independent software or hardware, that watches traffic on a network and collects statistics for a management station to read.

Plain language A remote monitoring agent watching network traffic and collecting statistics.

Used in RFC 1513 RFC 2819 RFC 3273 RFC 3287 RFC 3577

A Reconfigurable Optical Add/Drop Multiplexer, an optical node that can be reconfigured to add or drop wavelengths. A node that cannot be reconfigured is called a FOADM.

Plain language Reconfigurable Optical Add/Drop Multiplexer: an optical node redirecting wavelengths.

Used in RFC 6163 RFC 6205 RFC 7446 RFC 9094

The ability of a mobile device to move between different access points or networks while maintaining connectivity and authentication state.

Plain language Moving between networks while maintaining connectivity and authentication.

Used in RFC 2194 RFC 2477 RFC 2486 RFC 2905 RFC 2906 RFC 2989 RFC 4284 RFC 5296 RFC 6279 RFC 6342 RFC 6677 RFC 7315 RFC 7542 RFC 9878

A framework, with profiles for specific header sets, for shrinking packet headers on a link and restoring them at the other end.

Plain language A framework shrinking packet headers on a link and restoring them.

Used in RFC 3409 RFC 3759 RFC 4224 RFC 4247 RFC 5795 RFC 5856 RFC 5858

Encoding rules that convert ASN.1 values into XML documents, making ASN.1-defined data human-readable and compatible with standard XML tools.

Plain language Rules for converting structured data into human-readable XML format.

Used in RFC 4910 RFC 4911

Be liberal in what you accept and conservative in what you send. Software should tolerate unexpected input and unknown values from other hosts, while its own output sticks to the plain, well-defined forms of the protocol.

Plain language Be liberal in what you accept and conservative in what you send.

Used in RFC 1122 RFC 1123 RFC 1812 RFC 1958 RFC 2145 RFC 2360 RFC 3360 RFC 5198 RFC 7493 RFC 8504 RFC 9413

RObust Header Compression, a framework for compressing packet headers using profiles that each describe how to compress a certain protocol stack.

Plain language RObust Header Compression: compressing packet headers using protocol profiles.

Used in RFC 3374 RFC 3843 RFC 4019 RFC 4163 RFC 4224 RFC 4362 RFC 4997 RFC 5225 RFC 5795 RFC 5856 RFC 8285

A logical one-way connection that carries compressed packets from exactly one ROHC compressor to exactly one decompressor.

Used in RFC 3759 RFC 5225 RFC 5795

A compression protocol within the ROHC framework, written for one combination of headers and identified by a number such as 0x0004.

Used in RFC 3843 RFC 4163 RFC 4224 RFC 4362 RFC 5225

An access control scheme in which decisions are based on the role or group membership of the requester rather than their identity alone.

Plain language Access decisions based on role or group membership.

Used in RFC 3281 RFC 5755 RFC 8241 RFC 9310

A 32-bit counter in SRTP that records how many times the 16-bit RTP sequence number has wrapped. It is never sent in packets.

Plain language A 32-bit counter recording sequence number wraps in SRTP.

Used in RFC 3711 RFC 4383 RFC 4771 RFC 5669 RFC 7714 RFC 8870

The special entry at the top of an LDAP server that describes the server itself. Servers list the controls they support there, in the supportedControl attribute.

Plain language A special LDAP server entry describing the server itself.

Used in RFC 2829 RFC 3045 RFC 3674 RFC 3829 RFC 4512 RFC 4521 RFC 4527 RFC 4528

A child key derived from the EMSK, such as a USRK, DSRK or DSUSRK. It is used to derive further keys for protecting a specific service.

Plain language A child key derived from the EMSK used for protecting a specific service.

Used in RFC 5295 RFC 5749

In XMPP, a user's contact list, stored by the server. Each roster item identifies a contact by JID and tracks the subscription state and any groups or nicknames.

Plain language In XMPP, a user's contact list stored by the server.

Used in RFC 3921 RFC 4575 RFC 6121

The IETF's way of reaching decisions without voting. A large part of the community must agree, and anyone who disagrees must convince others or be overruled.

Plain language The IETF's decision-making process where most agree and dissenters convince others.

Used in RFC 2418 RFC 3844 RFC 3929 RFC 3935 RFC 4440 RFC 6701 RFC 7241 RFC 7282 RFC 7437 RFC 9280

The time between sending a packet to a node and receiving its reply back at the sender. It includes propagation, queuing and the processing time at the replying node.

Plain language The time between sending a packet and receiving its reply.

Used in RFC 1185 RFC 3393 RFC 4330 RFC 9198

The time for a message to travel to another node and for the reply to come back. It is often abbreviated RTT.

Plain language The time for a message to travel to another node and back.

Used in RFC 889 RFC 1305 RFC 1323 RFC 1574 RFC 1857 RFC 2140 RFC 2416 RFC 2488 RFC 2581 RFC 2679 RFC 2681 RFC 2861 RFC 2988 RFC 3390 RFC 3432 RFC 3708 RFC 3738 RFC 4654 RFC 5166 RFC 5348 RFC 5357 RFC 5690 RFC 6297 RFC 6298 and 22 more

Replacing many specific routes with one shorter-prefix route that covers them, so that routers elsewhere need fewer table entries.

Plain language Replacing many specific routes with one shorter-prefix route.

Used in RFC 1125 RFC 1322 RFC 1338 RFC 1380 RFC 1466 RFC 1467 RFC 1481 RFC 1518 RFC 1519 RFC 1520 RFC 1629 RFC 1655 RFC 1752 RFC 1771 RFC 1772 RFC 1773 RFC 1774 RFC 1787 RFC 1887 RFC 1888 RFC 1900 RFC 1930 RFC 1997 RFC 2008 and 55 more

An 8-octet value prepended to a route so that the same address used by different VPNs stays unique inside BGP.

Plain language An 8-octet value keeping the same address used by different VPNs unique.

Used in RFC 2547 RFC 4364 RFC 4365 RFC 4381 RFC 4659 RFC 6037 RFC 6368 RFC 6512 RFC 6514 RFC 6624 RFC 6882 RFC 7246 RFC 7611 RFC 7900 RFC 8294 RFC 8299 RFC 8466 RFC 9069 RFC 9136 RFC 9181 RFC 9182

A BGP mechanism that gives a route a penalty each time it changes and temporarily suppresses the route once the penalty passes a threshold. It is meant to reduce routing churn.

Plain language BGP temporarily suppresses routes that change frequently to reduce network instability.

Used in RFC 2439 RFC 3013 RFC 4098 RFC 7196 RFC 7454

The case where AS-A advertises routes it received from AS-B to its own neighbors, although AS-A is not a transit provider for the prefixes in those routes.

Plain language Advertising network directions received from another provider to your own customers.

Used in RFC 3784 RFC 7132 RFC 7908 RFC 9234

A Mobile IPv6 feature that lets packets flow directly between the mobile node and a correspondent node, bypassing the home agent for faster communication.

Plain language Direct packet delivery between a mobile device and its peer, skipping the home network intermediary.

Used in RFC 3775 RFC 4487 RFC 4889 RFC 6275

A digitally signed RPKI object in which an address block holder authorizes one Autonomous System to originate routes to listed prefixes. It is usually shortened to ROA.

Plain language Route Origin Authorization: a signed document authorizing an AS to originate routes.

Used in RFC 6482 RFC 6810 RFC 7115 RFC 7132 RFC 8209 RFC 8211 RFC 9582

A signed object (ROA) with which a prefix holder names the ASes that are authorized to originate routes for that prefix.

Plain language A signed record listing which networks may announce a given address block.

Used in RFC 6480 RFC 6482 RFC 6483 RFC 6491 RFC 6811 RFC 6907 RFC 7115 RFC 7132 RFC 7454 RFC 8205 RFC 8210 RFC 8360 RFC 8416 RFC 9319 RFC 9455 RFC 9774

A BGP speaker configured to advertise IBGP-learned routes to other internal BGP peers, normally forbidden in standard IBGP to prevent loops.

Plain language A router forwarding internal routing information between peers to reduce configuration.

Used in RFC 1966 RFC 2796 RFC 3107 RFC 3345 RFC 4456 RFC 5565 RFC 6198 RFC 6368 RFC 7524 RFC 7611 RFC 7705 RFC 9107 RFC 9541 RFC 9815

A BGP speaker at an Internet exchange that passes routes between peers and, by design, does not insert its own AS number into the AS_PATH.

Plain language A neutral routing hub passing network directions between exchange members without claiming ownership.

Used in RFC 6368 RFC 7947 RFC 7948 RFC 9117

A 16-bit field in a RIP-2 entry that must be kept and readvertised with the route, used for example to tell internal routes from ones imported from another protocol.

Plain language A label on a network route showing where it originally came from.

Used in RFC 1721 RFC 1723 RFC 1724 RFC 1745 RFC 2080 RFC 2081 RFC 2453 RFC 3101 RFC 4577 RFC 5130 RFC 7777 RFC 9067 RFC 9398 RFC 9403 RFC 9513

A label attached to a BGP route in a VPN that controls which VPN routing tables import the route.

Plain language A label on a VPN route determining which customer route tables receive it.

Used in RFC 4360 RFC 4364 RFC 4365 RFC 4382 RFC 4577 RFC 4659 RFC 4684 RFC 4761 RFC 6074 RFC 6368 RFC 6514 RFC 6624 RFC 7024 RFC 7209 RFC 7257 RFC 7432 RFC 7543 RFC 7611 RFC 7623 RFC 7734 RFC 7900 RFC 7988 RFC 8049 RFC 8294 and 9 more

The approach in which routing is performed in the IP layer, relying on IP routing and therefore supporting routing over possibly various types of interconnected links. In a route-over LoWPAN all routers, the 6LoWPAN Border Routers and 6LoWPAN Routers, perform IP routing within the stub network.

Plain language Routing that happens at the IP layer, so every router runs IP routing.

Used in RFC 6574 RFC 6606

A device that forwards packets between networks based on their IP destination. It does not forward link-layer broadcasts, which is why RARP stays on one segment.

Plain language A device forwarding data between networks based on IP destination addresses.

Used in RFC 321 RFC 331 RFC 334 RFC 335 RFC 395 RFC 791 RFC 814 RFC 950 RFC 951 RFC 994 RFC 1009 RFC 1015 RFC 1017 RFC 1054 RFC 1104 RFC 1112 RFC 1142 RFC 1177 RFC 1191 RFC 1195 RFC 1208 RFC 1242 RFC 1256 RFC 1269 and 279 more

A message IPv6 routers send to announce their presence together with various link and Internet parameters. Hosts use it to configure themselves.

Plain language A periodic announcement from a router containing network configuration details for hosts.

Used in RFC 2462 RFC 3041 RFC 4135 RFC 4191 RFC 4429 RFC 4862 RFC 4943 RFC 6104 RFC 6105 RFC 6496 RFC 6775 RFC 7051 RFC 7157 RFC 7359 RFC 7772 RFC 8043 RFC 8106 RFC 8319 RFC 8781 RFC 8801 RFC 8910

An option in the IP header that tells routers along the path to examine the packet more closely instead of just forwarding it.

Plain language A marker in a packet asking routers to inspect it closely instead of just forwarding.

Used in RFC 3376 RFC 3810 RFC 5350 RFC 5971 RFC 6398 RFC 7506 RFC 9570

A 32-bit number that uniquely identifies an OSPF router within the autonomous system.

Plain language A unique number identifying a router in OSPF routing.

Used in RFC 1131 RFC 1252 RFC 1253 RFC 1403 RFC 1745 RFC 1771 RFC 1793 RFC 2072 RFC 2178 RFC 2328 RFC 2370 RFC 2740 RFC 3101 RFC 3446 RFC 3480 RFC 3623 RFC 3630 RFC 3684 RFC 3784 RFC 4273 RFC 4444 RFC 4561 RFC 4652 RFC 4750 and 59 more

An ICMPv6 message sent by a host to request router advertisement and network configuration information from the local network.

Plain language A request a host sends asking routers for network configuration information.

Used in RFC 4135 RFC 7559 RFC 7772

The process of determining a path through a network and forwarding data packets along that path toward their destination.

Plain language Determining network paths and forwarding data toward destinations.

Used in RFC 975 RFC 1180 RFC 1479 RFC 1574 RFC 1677 RFC 2386 RFC 2450 RFC 2858 RFC 2909 RFC 3272 RFC 4292 RFC 4728 RFC 4907 RFC 5148 RFC 6552

The constrained path computation that picks both a route and a wavelength for an optical connection. It is usually shortened to RWA.

Plain language Selecting both a network path and light wavelength for optical connections.

Used in RFC 6163 RFC 7446 RFC 7449

In ASON, a partition of the network used for routing, identified in the control plane by an RA ID. Routing areas can contain smaller routing areas, which gives a hierarchy.

Plain language A hierarchical partition of a network used for optical routing.

Used in RFC 4258 RFC 4652 RFC 6827 RFC 8243

The protocol-independent ASON component that handles routing information for a routing area and exchanges it with peer controllers by working on the routing database.

Used in RFC 4258 RFC 6827

A set of routers and hosts that use the same routing protocol and routing procedures, wholly contained within a single Administrative Domain.

Plain language A group of routers and hosts using the same routing rules within an organization.

Used in RFC 1069 RFC 1136 RFC 1237 RFC 1388 RFC 1403 RFC 1518 RFC 1629 RFC 1745 RFC 1887 RFC 3787 RFC 5889

A data structure containing a list of routes, along with administrative data, that a router uses to forward packets.

Plain language A router's internal table of known routes and how to reach destinations.

Used in RFC 1724 RFC 4098 RFC 6396 RFC 6412 RFC 8022 RFC 8349 RFC 8430 RFC 8431 RFC 8671 RFC 9069 RFC 9914

The table of routes that a router holds and chooses from when deciding where to send traffic. Selected routes are then installed for forwarding.

Plain language Routing Information Base: a router's table of routes to choose from.

Used in RFC 1771 RFC 2439 RFC 3906 RFC 4098 RFC 7920 RFC 7921 RFC 7922 RFC 7938 RFC 9069 RFC 9972

A header field in Token Ring and source-routed frames that specifies the path the frame should take across a series of bridged segments.

Used in RFC 1220 RFC 1749

A LISP address that says where in the network an endpoint can currently be reached, usually the address of a tunnel router.

Plain language Routing Locator: a LISP address saying where an endpoint can currently be reached.

Used in RFC 5558 RFC 5720 RFC 6830 RFC 7215 RFC 9300 RFC 9301 RFC 9303 RFC 10040

In LISP, a topological address used for routing and forwarding through the Internet, bound to the host's current location.

Plain language The current IP address used for routing a host's traffic through the network.

Used in RFC 5558 RFC 6139 RFC 6830 RFC 6831 RFC 6832 RFC 6833 RFC 6835 RFC 6836 RFC 6837 RFC 7834 RFC 7835 RFC 7954 RFC 8060 RFC 8111 RFC 9299 RFC 9300 RFC 9301 RFC 9735 RFC 9962

The rules a network uses to decide which routes it accepts from neighbors, which it announces to them, and which it prefers.

Plain language Rules governing which network routes a provider accepts, shares, or prioritizes.

Used in RFC 1126 RFC 1479 RFC 1772 RFC 1786 RFC 2622 RFC 9067

A repository of routing policy information, such as which networks and autonomous systems exist and who may announce which prefixes. The Internet Routing Registry is a set of such repositories.

Plain language A public database listing network ownership and address block announcements.

Used in RFC 1787 RFC 2725 RFC 2769

A textual convention used for the status column of a conceptual table row. It lets a management station create, activate, suspend and delete rows with ordinary set operations.

Plain language A field indicating whether a table row is created, active, suspended or deleted.

Used in RFC 1447 RFC 1573 RFC 1724 RFC 1749 RFC 1902 RFC 1903 RFC 2494 RFC 2515 RFC 2579 RFC 2720 RFC 3289 RFC 3295 RFC 3813 RFC 3970 RFC 4087 RFC 4439 RFC 4546 RFC 5601 RFC 6527

A security flavor for ONC RPC that uses GSS-API mechanisms such as Kerberos to authenticate users to servers. NFSv4.1 clients and servers must implement it.

Plain language A secure method for authenticating users over remote procedure calls using Kerberos.

Used in RFC 2623 RFC 2624 RFC 3010 RFC 5403 RFC 7861 RFC 8000

A signed file that lists every signed object at an RPKI repository publication point, with a file name and hash for each. It lets a relying party detect missing, stale or altered files.

Plain language A signed inventory of cryptographically authenticated routing objects.

Used in RFC 7115 RFC 8211 RFC 8488 RFC 9286

The IPv6 Routing Protocol for Low-Power and Lossy Networks, a distance vector protocol that organizes devices into a root-based DODAG.

Plain language A routing protocol for battery-powered IoT devices with unreliable connections.

Used in RFC 6550 RFC 6551 RFC 6552 RFC 6554 RFC 6574 RFC 6719 RFC 6997 RFC 7102 RFC 8036 RFC 8138 RFC 8180 RFC 9008 RFC 9009 RFC 9010 RFC 9035 RFC 9685 RFC 9854 RFC 9866 RFC 9914 RFC 9926

A host attached to an RPL router that does not take part in RPL itself and relies on its router to inject the routes to its addresses. It is abbreviated RUL.

Used in RFC 9008 RFC 9010

The Routing Policy Specification Language, a text format in which routing registry objects are written as lines of attribute names and values.

Plain language A text-based language for describing routing policies and network ownership.

Used in RFC 2769 RFC 7909 RFC 7948 RFC 9632

A set of DNS resource records with the same owner name, class and type. DNSSEC signatures cover whole RRsets, not single records.

Plain language A group of matching DNS records signed together as a unit for security.

Used in RFC 2065 RFC 2136 RFC 2181 RFC 2308 RFC 2535 RFC 3007 RFC 3008 RFC 3226 RFC 4033 RFC 4034 RFC 4035 RFC 4501 RFC 4509 RFC 4592 RFC 4697 RFC 4956 RFC 5011 RFC 5074 RFC 5483 RFC 5507 RFC 5910 RFC 6672 RFC 6698 RFC 7344 and 19 more

Resource Record Signature. The DNSSEC record that holds a digital signature over an RRset, with inception and expiration times that bound its validity.

Plain language A digital signature proving a DNS record's authenticity and validity period.

Used in RFC 3755 RFC 4033 RFC 4034 RFC 4035 RFC 4398 RFC 4470 RFC 4509 RFC 4956 RFC 5011 RFC 5702 RFC 5910 RFC 5933 RFC 6605 RFC 6840 RFC 6841 RFC 6975 RFC 7129 RFC 7583 RFC 7646 RFC 8005 RFC 8080 RFC 8145 RFC 8749 RFC 8976 and 4 more

The recurrence rule property, whose value is a list of NAME=VALUE parts such as FREQ=WEEKLY;BYDAY=TU that describe a repeating event.

Plain language A compact rule describing repeating events, such as every Tuesday.

Used in RFC 2445 RFC 5545 RFC 7265 RFC 7529 RFC 7953 RFC 8984

A public key cryptosystem whose key consists of two numbers, commonly written e and n. It can be used to create and verify digital signatures.

Plain language A public-key encryption method used for digital signatures and secure communication.

Used in RFC 1319 RFC 1507 RFC 1825 RFC 2437 RFC 2459 RFC 2633 RFC 2792 RFC 3447 RFC 3565 RFC 3766 RFC 4050 RFC 4162 RFC 4432 RFC 4871 RFC 5201 RFC 5274 RFC 5702 RFC 5754 RFC 5959 RFC 6101 RFC 6655 RFC 7427 RFC 8017 RFC 8247 and 3 more

The Reliable Server Pooling protocol suite, which lets a client name a group of interchangeable servers by a pool handle and move to another server when one fails, without the application knowing the addresses in advance.

Plain language A way of reaching a group of servers that all do the same job by name rather than by address, so a failure can be handled by picking a different one.

Used in RFC 5351 RFC 5355 RFC 5356

The Resource ReSerVation Protocol, which sets up reservations of network resources for a flow using Path and Resv messages.

Plain language A protocol for reserving network bandwidth for specific traffic flows.

Used in RFC 1932 RFC 2105 RFC 2113 RFC 2207 RFC 2208 RFC 2209 RFC 2210 RFC 2211 RFC 2212 RFC 2215 RFC 2331 RFC 2375 RFC 2380 RFC 2381 RFC 2382 RFC 2386 RFC 2430 RFC 2490 RFC 2502 RFC 2638 RFC 2689 RFC 2745 RFC 2746 RFC 2747 and 45 more

RSVP extensions for Traffic Engineering, allowing explicit path setup and management of label switched paths in MPLS networks.

Plain language Protocol extensions for controlling the exact paths data takes through networks.

Used in RFC 3209 RFC 3210 RFC 3213 RFC 3468 RFC 3471 RFC 3473 RFC 3496 RFC 3970 RFC 4090 RFC 4124 RFC 4208 RFC 4783 RFC 4873 RFC 4875 RFC 4920 RFC 4974 RFC 5063 RFC 5151 RFC 5420 RFC 5443 RFC 5493 RFC 5520 RFC 5521 RFC 5695 and 31 more

A file synchronization tool that copies files between machines and, by default, skips any file whose last modification time and size already match on both sides.

Plain language A file synchronization tool copying only changed files between computers.

Used in RFC 6480 RFC 8182 RFC 9589

The RTP Control Protocol. It carries reports about delivery quality and session membership alongside an RTP stream.

Plain language A protocol carrying quality and membership reports alongside media streams.

Used in RFC 1889 RFC 1890 RFC 2326 RFC 2354 RFC 2508 RFC 2862 RFC 2959 RFC 3158 RFC 3264 RFC 3497 RFC 3550 RFC 3551 RFC 3556 RFC 3605 RFC 3611 RFC 3711 RFC 3714 RFC 3890 RFC 4175 RFC 4352 RFC 4570 RFC 4571 RFC 4585 RFC 4586 and 126 more

An extensible report carried in RTCP alongside the sender's own reports. Each kind of measurement is defined as a block with its own block type number, and the set of blocks used in a session can be agreed in the session description.

Plain language An extra report that travels with the periodic quality reports of a media session, carrying measurements that the standard reports do not cover.

Used in RFC 7002 RFC 7003

The Real-time Transport Protocol. It carries audio and video over IP with sequence numbers and timestamps so the receiver can play them back in order.

Plain language A protocol for delivering audio and video with proper sequencing and timing.

Used in RFC 741 RFC 1889 RFC 1890 RFC 2029 RFC 2032 RFC 2035 RFC 2038 RFC 2190 RFC 2198 RFC 2250 RFC 2326 RFC 2327 RFC 2343 RFC 2354 RFC 2429 RFC 2431 RFC 2435 RFC 2448 RFC 2507 RFC 2508 RFC 2658 RFC 2689 RFC 2705 RFC 2733 and 379 more

A mechanism that lets an RTP application notice extreme network congestion and react to it. It is a safety net and not a replacement for congestion control.

Used in RFC 8083 RFC 8834

Extra data placed in the header of an RTP packet using a general extension mechanism. It lets a sender attach small pieces of metadata to individual packets.

Plain language Additional metadata attached to media packets for application purposes.

Used in RFC 1889 RFC 6051 RFC 6904 RFC 8285 RFC 9335 RFC 9626

An intermediate system that combines RTP streams from several sources into one new stream and becomes the synchronization source of the result.

Plain language A system combining multiple media streams into one synchronized output.

Used in RFC 1889 RFC 2508 RFC 3550 RFC 4245 RFC 4353 RFC 4575 RFC 5104 RFC 5239 RFC 5686 RFC 5760 RFC 6341 RFC 6464 RFC 6465 RFC 6642 RFC 6679 RFC 6792 RFC 7201 RFC 7656 RFC 7667 RFC 7728 RFC 7866 RFC 8108 RFC 8286 RFC 8834 and 4 more

A group of participants exchanging RTP over one shared transport flow, sharing a single payload type space and a single RTCP reporting interval.

Used in RFC 8108 RFC 8860

An intermediate system that forwards RTP packets while keeping the original SSRC identifiers, for example converting encodings or bridging networks.

Plain language A relay forwarding media between networks while preserving source identification.

Used in RFC 1889 RFC 3550 RFC 5104 RFC 5686 RFC 5760 RFC 5762 RFC 6642 RFC 6679 RFC 6792 RFC 7022 RFC 7201 RFC 7656 RFC 7667 RFC 7728 RFC 7866 RFC 8079 RFC 8286 RFC 8861

The Real-Time Streaming Protocol, used to set up and control one or more media streams that deliver media to receivers.

Plain language A protocol for controlling media streaming sessions.

Used in RFC 2326 RFC 5583 RFC 6695 RFC 7825 RFC 8866

An unordered collection of authorization rules that together form a policy. Each rule pairs conditions with the permissions it grants when those conditions are all true.

Plain language A collection of if-then rules governing who may access what resources.

Used in RFC 2123 RFC 4745 RFC 5777

A compact way to describe a sequence by recording how long each run of identical values lasts instead of listing every value.

Plain language Data compression by noting repetition lengths instead of listing every value.

Used in RFC 803 RFC 804 RFC 3611 RFC 5725

A MIDI shortcut in which the status octet of a channel command is left out when it is the same as the previous one. RTP MIDI receivers must be able to decode it.

Plain language A MIDI shortcut omitting repeated command types to reduce message size.

Used in RFC 4695 RFC 6295