M

A hardware address assigned to a network interface. Ethernet MAC addresses are 48 bits long and are usually written as six hexadecimal bytes, such as 08:00:20:01:AB:C2.

Plain language A hardware address assigned to a network interface, typically written as six hexadecimal bytes.

Used in RFC 826 RFC 894 RFC 895 RFC 903 RFC 925 RFC 951 RFC 982 RFC 1103 RFC 1112 RFC 1180 RFC 1188 RFC 1229 RFC 1230 RFC 1231 RFC 1284 RFC 1285 RFC 1286 RFC 1329 RFC 1390 RFC 1434 RFC 1469 RFC 1493 RFC 1512 RFC 1513 and 205 more

A virtual routing and forwarding table for MAC addresses on a provider edge router. Each EVPN instance has one on each router that takes part.

Plain language A virtual routing and forwarding table for MAC addresses on a provider edge router.

Used in RFC 8388 RFC 9135 RFC 9136

A 16-by-16 pixel region in a video frame that is encoded and transmitted as a unit in H.261 compression.

Plain language A 16-by-16 pixel region in a video frame encoded as a unit.

Used in RFC 2032 RFC 2190 RFC 2429 RFC 6184 RFC 6386 RFC 7741 RFC 7867 RFC 9924

A fixed four-byte value, 99.130.83.99 (hex 63.82.53.63), placed at the start of the BOOTP vendor field to show that what follows is a list of tagged options. DHCP options use the same marker.

Plain language A fixed four-byte value marking the start of tagged DHCP or BOOTP options.

Used in RFC 1497 RFC 1533 RFC 1542 RFC 2131 RFC 2132 RFC 2637 RFC 5389 RFC 8489

A random 32-bit number each PPP end picks and sends in an LCP option. If a peer receives its own number back, the link is probably looped back to itself.

Plain language A random 32-bit number each PPP end sends to detect looped links.

Used in RFC 1331 RFC 1471 RFC 1548 RFC 1570 RFC 1661 RFC 1663 RFC 1989 RFC 2153 RFC 2363 RFC 2364 RFC 2854 RFC 3284 RFC 3302 RFC 3772 RFC 4288 RFC 6994 RFC 7527 RFC 8118 RFC 9277

The sender and recipient addresses given to SMTP in the MAIL FROM and RCPT TO commands. They are used for delivery and are separate from the From and To lines inside the message.

Plain language The sender and recipient addresses given to SMTP, separate from the message header.

Used in RFC 479 RFC 621 RFC 806 RFC 821 RFC 822 RFC 841 RFC 886 RFC 976 RFC 1148 RFC 1203 RFC 1486 RFC 1495 RFC 1528 RFC 1651 RFC 1711 RFC 1869 RFC 1894 RFC 2033 RFC 2156 RFC 2162 RFC 2476 RFC 2821 RFC 2822 RFC 3028 and 37 more

A host that receives mail not meant for itself and passes it on toward its destination, which is how SMTP can carry mail across different networks.

Plain language A host that receives mail not meant for itself and passes it on.

Used in RFC 754 RFC 763 RFC 780 RFC 785 RFC 786 RFC 788 RFC 799 RFC 805 RFC 819 RFC 821 RFC 897 RFC 915 RFC 921 RFC 974 RFC 987 RFC 993 RFC 1204 RFC 1211 RFC 1460 RFC 1506 RFC 1649 RFC 1651 RFC 1711 RFC 1838 and 27 more

In RFC 5322, a destination for mail, written as an address like user@example.com or with a display name, John Doe <john@example.com>.

Plain language In RFC 5322, a mail destination written as an address or with a display name.

Used in RFC 196 RFC 278 RFC 303 RFC 458 RFC 469 RFC 475 RFC 491 RFC 510 RFC 524 RFC 539 RFC 543 RFC 555 RFC 621 RFC 630 RFC 680 RFC 720 RFC 744 RFC 751 RFC 754 RFC 757 RFC 759 RFC 763 RFC 767 RFC 780 and 149 more

The place on a server where a user's incoming mail is held until the client collects it. In POP3 the server locks the maildrop for the whole session.

Plain language A folder on a mail server that holds incoming messages until the recipient downloads them.

Used in RFC 1081 RFC 1082 RFC 1225 RFC 1339 RFC 1460 RFC 1725 RFC 1939 RFC 2449 RFC 6856

A named group of recipients who share a common address, allowing a single message to be delivered to multiple people.

Plain language One email address that automatically forwards messages to a group of people.

Used in RFC 720 RFC 1739 RFC 1855 RFC 2014 RFC 2369 RFC 2634 RFC 3131 RFC 3683 RFC 6449 RFC 6701 RFC 6783 RFC 7154 RFC 7960

In MPLS-TP, a management unit consisting of endpoints (MEPs) that bound the OAM scope for monitoring and managing a transport path or segment.

Plain language A network section with endpoints that define where monitoring begins and ends.

Used in RFC 7087 RFC 7174 RFC 8150

A set of Maintenance Entities associated with the same service instance, used to organize OAM monitoring across multiple managed points.

Plain language A set of monitored sections organized to manage one network service.

Used in RFC 6136 RFC 6370 RFC 6371 RFC 6426

An end point of a monitored path in MPLS-TP OAM, abbreviated MEP. It is where OAM messages about that path are sent and received.

Plain language An endpoint where network monitoring messages are sent and received for a particular path.

Used in RFC 6136 RFC 6427 RFC 6428 RFC 7455 RFC 8531 RFC 9551

Setting up a new path and moving traffic onto it before the old path is torn down. This avoids a gap in delivery.

Plain language Establishing a new connection before closing the old one, preventing service interruption.

Used in RFC 3209 RFC 3210 RFC 4192 RFC 4736 RFC 4872 RFC 4873 RFC 4875 RFC 5557 RFC 5710 RFC 5712 RFC 7010 RFC 7823 RFC 8131 RFC 8149

An attack in which someone secretly sits between two parties, relaying and possibly altering their traffic while each believes it is talking directly to the other.

Plain language An attack where someone secretly intercepts and may alter communication between two parties.

Used in RFC 3329 RFC 3748 RFC 3833 RFC 5801 RFC 6181 RFC 6797 RFC 6876 RFC 7029 RFC 7171 RFC 7201 RFC 7619 RFC 7924 RFC 8600 RFC 8633 RFC 8826 RFC 8827 RFC 9048 RFC 9463 RFC 9588 RFC 9891 RFC 9985

An attack in which someone sits between two parties and pretends to each to be the other, so they can watch or change the traffic. SSH defends against it by checking the server's host key.

Plain language An attack where someone secretly intercepts and may alter communication between two parties.

Used in RFC 2246 RFC 2371 RFC 2595 RFC 2607 RFC 2617 RFC 2817 RFC 2818 RFC 2829 RFC 2830 RFC 2945 RFC 3118 RFC 3157 RFC 3207 RFC 3552 RFC 3631 RFC 3656 RFC 3694 RFC 3756 RFC 3760 RFC 3767 RFC 3788 RFC 3837 RFC 3887 RFC 3892 and 134 more

A single item in a MIB, such as a setting or a counter, that a management protocol like SNMP can read and sometimes change.

Plain language A setting or counter on a network device that can be monitored or adjusted remotely.

Used in RFC 1065 RFC 1156 RFC 1157 RFC 1158 RFC 1189 RFC 1213 RFC 1229 RFC 1230 RFC 1270 RFC 1285 RFC 1441 RFC 1442 RFC 1447 RFC 1512 RFC 1513 RFC 1573 RFC 1666 RFC 1749 RFC 1903 RFC 1904 RFC 1905 RFC 2108 RFC 2494 RFC 2571 and 18 more

A standardized catalog of data objects that network devices expose via SNMP, allowing remote monitoring and configuration.

Plain language A catalog of information about a network device that can be read and sometimes changed remotely.

Used in RFC 1098 RFC 1248 RFC 1441 RFC 1442 RFC 1448 RFC 1611 RFC 1666 RFC 2012 RFC 2837 RFC 3410 RFC 3460 RFC 3591 RFC 3813 RFC 4113 RFC 5591 RFC 5728 RFC 6632

A database of managed objects, described in a standard format, that a network device exposes for monitoring and control via SNMP.

Plain language A standardized collection of settings and counters that a network device exposes for remote monitoring.

Used in RFC 1657 RFC 2108 RFC 2790 RFC 3276 RFC 5066

An access model in which every subject and object carries a security label, and a system-wide policy decides access from those labels.

Plain language A security system where access is controlled by comparing security labels on files and users.

Used in RFC 5570 RFC 7204 RFC 7569 RFC 7861 RFC 7862 RFC 9478

A feature or algorithm that every compliant implementation must include, so that any two implementations have at least one option in common.

Plain language A required feature that every implementation must include for compatibility.

Used in RFC 7202 RFC 7696 RFC 8221 RFC 8247 RFC 9904

A mobile ad hoc network, in which connectivity to some destinations is provided by forwarding through intermediate devices.

Plain language A wireless network where moving devices relay messages to reach distant destinations.

Used in RFC 3684 RFC 5148 RFC 5497 RFC 5498 RFC 5614 RFC 6130 RFC 6621 RFC 6779 RFC 7038 RFC 7181 RFC 7182 RFC 7183 RFC 7185 RFC 7188 RFC 7367 RFC 7722 RFC 7939 RFC 7985 RFC 8218 RFC 8245 RFC 8629

In the context of XML signatures, a collection of references to the objects being signed, specifying what content the signature covers.

Plain language A list specifying which items are covered by a digital signature.

Used in RFC 2807 RFC 6480 RFC 6481 RFC 8216 RFC 9829

A model, defined in RFC 8520, in which a manufacturer publishes a file describing a device, which can include the network access it needs. RFC 9472 extends it.

Plain language A file from a manufacturer describing a device's network access requirements.

Used in RFC 9238 RFC 9472

A file published by a device maker that describes which network resources the device needs to reach. A network can use it to build access control rules for that device.

Plain language A file from the manufacturer describing which network services a device needs to access.

Used in RFC 9726 RFC 9761

The local store where an ITR keeps EID-to-RLOC mappings it has learned from Map-Replies. Each entry is kept for the time given in the record's TTL.

Plain language A local cache storing learned address mappings so repeated lookups are avoided.

Used in RFC 6830 RFC 7052 RFC 9299 RFC 9300 RFC 9301

A LISP device that accepts Encapsulated Map-Requests from Ingress Tunnel Routers and finds, through a mapping database, the Egress Tunnel Router that can answer them.

Plain language The helper that finds the right server to answer a lookup for an address.

Used in RFC 6830 RFC 6835 RFC 6836 RFC 7215 RFC 9301

A LISP device that learns EID-Prefix mappings from an Egress Tunnel Router and publishes them in a mapping database, so that Map-Requests for those prefixes can be answered.

Plain language The helper that holds the published mappings and hands them out when asked.

Used in RFC 6830 RFC 6835 RFC 7215 RFC 9301

Multiple Access Protocol over SONET/SDH, a link-layer protocol that lets several nodes share SONET/SDH links through a Frame Switch.

Plain language A protocol allowing multiple devices to share a single high-speed optical link.

Used in RFC 2172 RFC 2173 RFC 2174 RFC 2175 RFC 3422

A single bit in the RTP header whose meaning depends on the payload format. For DV video it is set on the last packet of a frame.

Plain language A bit in a video packet indicating whether it is the final packet of a frame.

Used in RFC 3640 RFC 4103 RFC 4348 RFC 6469

The Multicast Address Resolution Server, a server that distributes multicast group membership information to endpoints on an ATM network. Its clients are grouped into a cluster.

Plain language A server that tracks which devices belong to each multicast group on an ATM network.

Used in RFC 2022 RFC 2226 RFC 2417 RFC 2443

A deterministic function that stretches an input of variable length into an output of a chosen length that looks random. RSAES-OAEP and RSASSA-PSS use it to hide parts of the encoded message.

Used in RFC 3447 RFC 8017

Every client-to-server frame has its payload XORed with a 32-bit masking key that travels in the frame header. It is meant to stop a client from being used to craft traffic that could confuse intermediaries.

Plain language Encoding client messages with a key to prevent misuse by network intermediaries.

Used in RFC 2437 RFC 2522 RFC 3415 RFC 4625 RFC 6455

The SNMP agent that talks to managers and passes requests on to AgentX subagents, which implement parts of the MIB it has registered for them.

Plain language The main SNMP agent that receives management requests and forwards them to specialized agents.

Used in RFC 2741 RFC 2742

A text file listing the resource records of one zone, edited by the zone's administrator and loaded by a name server as authoritative data.

Plain language The primary file containing authoritative DNS records for a domain zone.

Used in RFC 883 RFC 4027

A random secret handed to SRTP by key management. All session keys for encryption, authentication and salting are derived from it.

Plain language A secret key from which all other encryption keys are derived.

Used in RFC 2246 RFC 3118 RFC 3711 RFC 3748 RFC 4186 RFC 4187 RFC 4346 RFC 4563 RFC 4568 RFC 5091 RFC 5191 RFC 5247 RFC 5295 RFC 5408 RFC 5433 RFC 5448 RFC 5705 RFC 5794 RFC 5926 RFC 6188 RFC 6358 RFC 6678 RFC 6696 RFC 6734 and 9 more

The master key generated and privately kept by a Key Management Service, used to generate the private keys of the users that it provisions. In SAKKE it is an integer in the range 2 to q-1, and it must never be revealed to any other entity.

Plain language The secret at the centre of the service that every user key is derived from.

Used in RFC 6101 RFC 6508

Key material exported by an EAP method after a successful authentication. Other keys, such as those for a security association, are derived from it.

Plain language Key material generated after authentication from which other session keys are derived.

Used in RFC 4186 RFC 4187 RFC 4851 RFC 5169 RFC 5216 RFC 5836 RFC 6678 RFC 6696 RFC 7831 RFC 9427 RFC 9820 RFC 9930

A rule that tells an LDAP server how to compare two values, for example for equality or for ordering. Each attribute type names the rules that apply to it.

Plain language A rule specifying how an LDAP server compares values for equality or ordering.

Used in RFC 2252 RFC 2254 RFC 2891 RFC 3112 RFC 3687 RFC 3698 RFC 4517 RFC 4523 RFC 4530 RFC 7612

The standardization state of a protocol, indicating whether it is a standard, draft standard, proposed standard, experimental, informational, or historic.

Plain language A classification indicating whether a protocol is experimental, proposed, standard, or obsolete.

Used in RFC 1310 RFC 1602 RFC 1800 RFC 2300

A pair of spanning trees rooted at the same node that give every other node two paths to the root sharing the fewest possible nodes and links. They are named MRT-Blue and MRT-Red.

Plain language Two independent paths to a destination with minimal overlap, for redundancy.

Used in RFC 7811 RFC 7812 RFC 8320

A TCP option, sent in a SYN, that tells the peer the largest segment payload the sender is willing to receive. Without it, 536 bytes is assumed for IPv4 and 1220 for IPv6.

Plain language A TCP parameter specifying the largest packet data a device can receive.

Used in RFC 793 RFC 879 RFC 1191 RFC 1201 RFC 1981 RFC 2140 RFC 2147 RFC 2385 RFC 2414 RFC 2581 RFC 2675 RFC 2923 RFC 3081 RFC 3150 RFC 3390 RFC 4404 RFC 4413 RFC 4614 RFC 5681 RFC 5682 RFC 5690 RFC 6691 RFC 6817 RFC 6928 and 12 more

The largest number of segment identifiers (SIDs) that a node or link can handle when imposing a SID stack on a packet.

Plain language The maximum number of routing labels a router can add to a single packet.

Used in RFC 8476 RFC 8491 RFC 8662 RFC 8814 RFC 9702

An optional ROA attribute giving the longest prefix length the AS is authorized to advertise. It lets one entry stand for many more-specific prefixes.

Plain language A maximum prefix length that authorizes a range of smaller address blocks.

Used in RFC 9319 RFC 9582

A one-way function that turns any input into a 16-byte fingerprint. RADIUS uses it to hide passwords and to sign replies, though MD5 is no longer considered strong.

Plain language A one-way function that creates a unique fingerprint from data, now considered weak for security.

Used in RFC 1186 RFC 1321 RFC 1352 RFC 1423 RFC 1460 RFC 1724 RFC 1725 RFC 1751 RFC 1760 RFC 1810 RFC 1828 RFC 1852 RFC 1864 RFC 1890 RFC 1910 RFC 1964 RFC 1994 RFC 2002 RFC 2058 RFC 2069 RFC 2082 RFC 2085 RFC 2104 RFC 2107 and 110 more

Multicast DNS, defined in RFC 6762. Hosts on a local link send DNS-format queries to a multicast address and the host that owns the name answers, so names can be resolved with no DNS server.

Plain language A method where local devices announce their names on the network instead of using a central directory.

Used in RFC 4795 RFC 5687 RFC 6055 RFC 6641 RFC 6760 RFC 6762 RFC 6763 RFC 6804 RFC 7368 RFC 7558 RFC 7605 RFC 7788 RFC 8117 RFC 8155 RFC 8222 RFC 8764 RFC 8766 RFC 8882 RFC 8995 RFC 9665 RFC 9726

A rating of media quality, usually on a scale from 1 (unacceptable) to 5 (excellent), originally the mean of scores given by people in subjective tests. Objective algorithms can estimate it automatically.

Used in RFC 7266 RFC 7875

In an LMAP platform, the element that actually performs measurements. It follows instructions from exactly one Controller at a time and reports results to one or more Collectors.

Plain language A device that runs network measurements and reports the results to controllers.

Used in RFC 6038 RFC 7536 RFC 7594 RFC 8193 RFC 9341

The process of verifying that a requested multimedia stream (audio, video, data) is authorized by policy before network resources are reserved to deliver it.

Plain language Verifying that a user has permission to use requested network resources for media.

Used in RFC 3313 RFC 3521

A source of media (video, audio, or timed text) that a Media Provider can encode and send, such as a camera, microphone, screen, or mixed content from multiple sources.

Plain language A source of video, audio, or text such as a camera or microphone that can be transmitted.

Used in RFC 8845 RFC 8847

Loss of the first part of a media stream because packets arrive before the receiver is able to process them.

Plain language Loss of the first part of a media stream when packets arrive before the receiver is ready.

Used in RFC 3960 RFC 5027 RFC 5479

A named label that describes a capability of a device, such as supporting ICE. In SIP such tags can be carried in the Contact header field.

Plain language A label describing a device capability such as video support.

Used in RFC 2506 RFC 2534 RFC 2879 RFC 2913 RFC 5768 RFC 8848

A network device that converts media (usually voice) between telephone networks and IP networks, controlled by a call agent via MGCP commands.

Plain language A device that converts voice signals between telephone networks and IP networks.

Used in RFC 2705 RFC 2805 RFC 2885 RFC 3015 RFC 3398 RFC 3435 RFC 3441 RFC 3525 RFC 3660 RFC 4233 RFC 5347

The node that performs call processing for signaling that a gateway has backhauled to it. In IUA it is the MGC, where the Q.931 layer runs.

Plain language The system that controls how a media gateway processes calls and signals.

Used in RFC 2719 RFC 2885 RFC 3015 RFC 3372 RFC 3398 RFC 3525 RFC 4233

A server that performs media services such as playing audio, mixing streams or running interactive voice response, under the control of an Application Server.

Plain language A server that handles audio and video processing tasks for applications.

Used in RFC 2326 RFC 4240 RFC 4722 RFC 5022 RFC 5567 RFC 5616 RFC 5707 RFC 6231 RFC 6505 RFC 6917 RFC 7245

A label of the form type/subtype, such as text/plain or image/jpeg, carried in the Content-Type header. The type gives the general kind of data and the subtype the specific format.

Plain language A label like text/plain or image/jpeg identifying what type of data a message contains.

Used in RFC 767 RFC 910 RFC 1341 RFC 1524 RFC 1590 RFC 1766 RFC 1767 RFC 1895 RFC 1896 RFC 2017 RFC 2045 RFC 2046 RFC 2048 RFC 2049 RFC 2077 RFC 2083 RFC 2122 RFC 2158 RFC 2160 RFC 2169 RFC 2220 RFC 2295 RFC 2296 RFC 2298 and 304 more

A middlebox or gateway that can parse parts of the RTP payload and react to what it finds. For example, it can drop the least important packets when a link is congested.

Plain language A network device that examines media packets and can prioritize or discard them as needed.

Used in RFC 6184 RFC 6190 RFC 9584

The part of an IEEE 802.3 Ethernet port that connects a device or repeater to the physical medium, such as copper or fiber. A MAU type fixes the speed, cabling and duplex mode.

Plain language The interface connecting a device or repeater to physical Ethernet cabling.

Used in RFC 3636 RFC 4836

Mobile Equipment Identity. A globally unique identifier assigned by 3GPP2 standards bodies and burned into every 3GPP2 mobile device. It uniquely identifies the hardware device (not the user or SIM card).

Used in RFC 8464 RFC 8465

A function that needs a large amount of memory as well as time to compute, so that building faster hardware gives an attacker less of an advantage.

Plain language A computational function requiring large memory as well as time, resistant to hardware speedup.

Used in RFC 7914 RFC 9106

The router where a backup path rejoins the primary path. There can be several Merge Points for a single protected node.

Plain language A router where a backup path rejoins the primary path after protection.

Used in RFC 4090 RFC 4561 RFC 7431 RFC 7715 RFC 8271 RFC 8796 RFC 9705

A binary tree in which each interior node holds the hash of its two children. The value at the root commits to everything at the leaves.

Plain language A tree structure where each node contains a hash of its children, securing all data below.

Used in RFC 4998 RFC 6962 RFC 8391 RFC 8554 RFC 8708 RFC 9162 RFC 9708 RFC 9802 RFC 9942 RFC 10033 RFC 10049

A network where devices relay messages for each other through multiple hops, allowing communication to continue even if direct links are blocked or fail.

Plain language A network where devices relay messages to each other, allowing communication through multiple hops.

Used in RFC 7298 RFC 7548 RFC 8240 RFC 8966

A design in which multi-hop forwarding happens below the IP layer, so the whole mesh appears to IP as a single link. The alternative, route-over, forwards packets at the IP layer.

Used in RFC 6574 RFC 6606

A short, fixed-length value computed from a message and a secret key. The receiver recomputes it to check that the message has not been altered.

Plain language A code computed from a message that verifies it has not been altered.

Used in RFC 2385 RFC 2660 RFC 2845 RFC 3566 RFC 3652 RFC 3686 RFC 4082 RFC 4187 RFC 4210 RFC 4230 RFC 4347 RFC 4366 RFC 4442 RFC 4822 RFC 4895 RFC 5084 RFC 5647 RFC 5830 RFC 5925 RFC 5926 RFC 6234 RFC 6476 RFC 7165 RFC 7182 and 6 more

A short value computed from a message and a shared secret that lets the receiver detect any change to the message. SSH includes a packet sequence number in the MAC input to prevent replay.

Plain language A short value computed from a message and shared secret that detects message changes.

Used in RFC 2104 RFC 2403 RFC 2410 RFC 2743 RFC 2841 RFC 3394 RFC 3566 RFC 3610 RFC 4225 RFC 4251 RFC 4253 RFC 4344 RFC 4383 RFC 4418 RFC 4493 RFC 4758 RFC 4771 RFC 5083 RFC 5282 RFC 5487 RFC 5926 RFC 6010 RFC 6101 RFC 6584 and 26 more

A fixed-size fingerprint or hash value computed from data using a digest algorithm such as SHA-1. Changes to the data produce a completely different digest, allowing detection of tampering.

Used in RFC 2138 RFC 2802 RFC 3377 RFC 5922 RFC 7693

A short fixed-size value computed from data with a hash function. Changing the data, even slightly, changes the digest, so it works as a fingerprint of the content.

Plain language A unique fingerprint of data that changes if the data is modified even slightly.

Used in RFC 1036 RFC 1115 RFC 1153 RFC 1186 RFC 1319 RFC 1320 RFC 1321 RFC 1352 RFC 1423 RFC 1446 RFC 1704 RFC 1750 RFC 1810 RFC 1847 RFC 1864 RFC 2095 RFC 2104 RFC 2154 RFC 2202 RFC 2311 RFC 2315 RFC 2404 RFC 2437 RFC 2574 and 94 more

A message generated on the recipient side that reports what happened to a mail message, for example that it was refused or deleted. It is usually abbreviated MDN.

Plain language A notification informing the sender what happened to their email message.

Used in RFC 2532 RFC 3335 RFC 3798 RFC 3886 RFC 3888 RFC 4130 RFC 5429 RFC 6533 RFC 9007

The rules that tell a receiver where one message ends and the next begins. In HTTP/1.1 they are Content-Length, chunked coding, or closing the connection.

Plain language Rules that indicate where one message ends and the next message begins.

Used in RFC 58 RFC 618 RFC 1055 RFC 1153 RFC 1154 RFC 1547 RFC 1618 RFC 1625 RFC 1662 RFC 2126 RFC 3080 RFC 3257 RFC 3286 RFC 4037 RFC 4571 RFC 4582 RFC 4767 RFC 4824 RFC 4975 RFC 5044 RFC 5045 RFC 5425 RFC 5460 RFC 5734 and 15 more

A code computed from a message that allows the recipient to verify that the message has not been altered in transit.

Plain language A code verifying that a message was not altered during transmission.

Used in RFC 1040 RFC 1113 RFC 1421 RFC 1423 RFC 3335 RFC 4763 RFC 5402

A value computed over a message so the receiver can check it was not altered. In GSS it is produced by the GetMIC operation.

Plain language A code proving that a message was not altered.

Used in RFC 4462 RFC 5403 RFC 8004

A set of version-specific procedures for building and taking apart SNMP messages and for asking a security model to protect them. Several models can exist at the same time.

Plain language A procedure for assembling and processing SNMP messages with security.

Used in RFC 2272 RFC 2571 RFC 3412

The position of a message in an IMAP mailbox, counted from the start. It can shift when earlier messages are expunged.

Plain language The position of a message in a mailbox, which changes when earlier messages are deleted.

Used in RFC 2060 RFC 5465 RFC 7162 RFC 9051 RFC 9586

The server process that accepts new messages from mail programs, normally on port 587, checks that the sender is authorized, and either delivers the message or relays it onward as an SMTP client.

Plain language A mail server that accepts messages from programs and relays them to their destination.

Used in RFC 2476 RFC 4409 RFC 4468 RFC 4865 RFC 4871 RFC 5068 RFC 5598 RFC 6186 RFC 6409 RFC 6710 RFC 7960 RFC 8314 RFC 8617 RFC 9422

The practice of asking a mail system for the current status of a message that has already been sent, used when neither a delivery status notification nor a message disposition notification has arrived.

Plain language Asking a mail server where a message has got to, for a message that was never confirmed.

Used in RFC 3886 RFC 3888

A mail server that speaks SMTP to accept messages from an MSA or another MTA and then delivers them or relays them to the next MTA. MTAs are not supposed to alter message text beyond adding trace headers.

Plain language A mail server that relays messages to other servers without modifying them.

Used in RFC 821 RFC 841 RFC 934 RFC 987 RFC 989 RFC 1137 RFC 1138 RFC 1210 RFC 1327 RFC 1421 RFC 1616 RFC 1649 RFC 1653 RFC 1711 RFC 1801 RFC 1847 RFC 1891 RFC 1894 RFC 2015 RFC 2049 RFC 2156 RFC 2249 RFC 2369 RFC 2476 and 71 more

The program that composes and submits new messages and shows delivered ones, often with a user interface. A mail app on a phone or computer is an MUA.

Plain language The email program or app you use to read and send messages.

Used in RFC 934 RFC 1343 RFC 1421 RFC 1524 RFC 2156 RFC 2183 RFC 2369 RFC 2476 RFC 2505 RFC 2524 RFC 2532 RFC 2542 RFC 2919 RFC 3249 RFC 3458 RFC 3464 RFC 3503 RFC 3798 RFC 3865 RFC 4409 RFC 4865 RFC 4871 RFC 4952 RFC 5068 and 23 more

A header field holding a globally unique identifier for one message, written in angle brackets. Replies cite it in In-Reply-To and References so clients can build conversations.

Plain language A unique identifier for each email allowing email clients to group conversations.

Used in RFC 533 RFC 534 RFC 680 RFC 806 RFC 807 RFC 808 RFC 809 RFC 841 RFC 850 RFC 977 RFC 987 RFC 1036 RFC 1138 RFC 1203 RFC 1703 RFC 1820 RFC 1872 RFC 2059 RFC 2076 RFC 2111 RFC 2262 RFC 2359 RFC 2392 RFC 2557 and 32 more

A single connection between two explicitly identified GIST nodes that are neighbours on the signalling path. It is bidirectional, may carry signalling for several flows at once, and is set up and torn down by GIST itself rather than by the signalling application.

Plain language A connection between two neighbouring signalling nodes. GIST sets it up on its own and hides it from the application above.

Used in RFC 5971 RFC 6084

Data about data; information that describes properties of a resource such as its name, type, location, size and modification status.

Plain language Information describing properties of data such as its type, size, or modification date.

Used in RFC 1728 RFC 1807 RFC 5013 RFC 5812 RFC 6973 RFC 8153 RFC 8165 RFC 9065

The NFSv4 server in a pNFS system. It provides pNFS layouts to clients and handles operations on file metadata such as names and attributes.

Plain language A server managing file metadata and telling clients where data is stored.

Used in RFC 5661 RFC 6688 RFC 8434 RFC 8435 RFC 9766

The Management Information Base. A standard collection of named values, such as counters and tables, that a management protocol can read or set on a managed host or gateway.

Plain language A collection of values that a network device exposes for remote monitoring and control.

Used in RFC 1023 RFC 1052 RFC 1065 RFC 1066 RFC 1067 RFC 1076 RFC 1095 RFC 1109 RFC 1123 RFC 1155 RFC 1156 RFC 1157 RFC 1158 RFC 1162 RFC 1189 RFC 1207 RFC 1208 RFC 1212 RFC 1213 RFC 1214 RFC 1215 RFC 1227 RFC 1229 RFC 1230 and 548 more

A formal description of managed objects (settings, counters, and status values) that a network device exposes to SNMP. Defined using the Structure of Management Information (SMI).

Plain language A formal specification of settings and counters that SNMP can monitor on a device.

Used in RFC 1065 RFC 1227 RFC 1229 RFC 1441 RFC 1573 RFC 1903 RFC 1904 RFC 2108 RFC 2515 RFC 2575 RFC 2666 RFC 2790 RFC 2934 RFC 3216 RFC 3289 RFC 3410 RFC 3512 RFC 3559 RFC 3577 RFC 3593 RFC 3635 RFC 3705 RFC 3780 RFC 3812 and 16 more

A named subset of the managed objects in an SNMP context, built from included and excluded subtrees. Access control grants a group rights in terms of such views.

Plain language A subset of available data that a person is allowed to access in SNMP.

Used in RFC 1157 RFC 1351 RFC 1447 RFC 1905 RFC 1909 RFC 2108 RFC 2265 RFC 2275 RFC 2575 RFC 3415 RFC 3512 RFC 3877

A unique enumerated integer value assigned by IANA to each registered charset. The values are defined by and used in the Printer MIB.

Plain language A unique numeric identifier assigned by IANA to a registered character set.

Used in RFC 2278 RFC 2978

A measurement session set up on a single member link of a LAG, so that each link gets its own performance numbers. All micro sessions of a LAG share the same sender and receiver IP addresses.

Plain language A separate performance measurement on one link in a group of bundled links.

Used in RFC 9533 RFC 9534

A short-lived forwarding loop that appears while routers update their forwarding tables at different times after a topology change.

Plain language A temporary loop where routers forward packets back and forth due to staggered updates.

Used in RFC 5286 RFC 5714 RFC 5715 RFC 6413 RFC 6571 RFC 7490 RFC 8333 RFC 8405 RFC 9843 RFC 9855

A short burst of packets that causes drops even though the link is not under sustained congestion.

Used in RFC 8238 RFC 8239

A single, specific stream of packets between one application at one end and another application at the other, as opposed to a large aggregate of many streams. Routers that preserve packet order do so per microflow.

Used in RFC 2597 RFC 9956

A device on the path such as a firewall, load balancer or proxy that handles traffic without being the endpoint.

Plain language A device like a firewall or proxy that processes traffic between two endpoints.

Used in RFC 3168 RFC 3234 RFC 3238 RFC 3303 RFC 3304 RFC 3323 RFC 3360 RFC 3424 RFC 3540 RFC 3724 RFC 3726 RFC 3752 RFC 3835 RFC 3917 RFC 3989 RFC 4037 RFC 4080 RFC 4097 RFC 4236 RFC 4340 RFC 4540 RFC 4571 RFC 4924 RFC 4942 and 121 more

Musical Instrument Digital Interface, a standard protocol for digital communication between musical instruments, synthesizers, and computers.

Plain language A standard protocol for digital communication between musical instruments and computers.

Used in RFC 4613 RFC 4695 RFC 4696 RFC 6295

Multimedia Internet KEYing, a key management protocol that sets up session keys for real-time multimedia in a single round trip. It is defined in RFC 3830.

Plain language A protocol for quickly establishing encryption keys between participants in a multimedia session.

Used in RFC 4442 RFC 4563 RFC 4567 RFC 4650 RFC 4909 RFC 5479

Multipurpose Internet Mail Extensions. A set of standards (RFC 2045 to RFC 2049) that let Internet mail carry non-ASCII text, attachments, images and nested messages by adding headers that describe the body.

Plain language A standard for adding attachments, images, and non-ASCII text to plain email.

Used in RFC 821 RFC 850 RFC 1040 RFC 1049 RFC 1341 RFC 1342 RFC 1344 RFC 1399 RFC 1426 RFC 1427 RFC 1428 RFC 1437 RFC 1456 RFC 1477 RFC 1486 RFC 1489 RFC 1494 RFC 1495 RFC 1496 RFC 1505 RFC 1521 RFC 1522 RFC 1523 RFC 1524 and 295 more

A label that describes what kind of data is in a message body, such as text/plain or image/jpeg, allowing mail readers to know how to handle it.

Plain language A label identifying message content type, such as text/plain or image/jpeg.

Used in RFC 1049 RFC 1341 RFC 1522 RFC 1523 RFC 1766 RFC 1844 RFC 1894 RFC 2077 RFC 3156 RFC 3391 RFC 3798 RFC 3839 RFC 3862 RFC 3886 RFC 4134 RFC 5402 RFC 6047 RFC 6381 RFC 7193

Either a message or a body part. Every entity has a header and a body, and the structure of a MIME message is recursive, so an entity can contain further entities.

Plain language Anything in a MIME message that has its own headers and its own body.

Used in RFC 1341 RFC 2392

A label that identifies the type of content in a file or message, so programs know how to handle it. Consists of a type and subtype (e.g., text/plain, image/jpeg, application/cms).

Plain language A label identifying content type so software knows how to process a file or message.

Used in RFC 1341 RFC 2911 RFC 3236 RFC 3555 RFC 3640 RFC 4337 RFC 5402 RFC 6047 RFC 6381 RFC 7193

A label such as text/calendar that tells a program what kind of data a body part holds, so it can pass it to the right application.

Plain language A label indicating the type of data in a message part.

Used in RFC 807 RFC 809 RFC 850 RFC 1049 RFC 1343 RFC 1494 RFC 1495 RFC 1521 RFC 1563 RFC 1740 RFC 1842 RFC 1844 RFC 1847 RFC 1872 RFC 1873 RFC 1874 RFC 1892 RFC 1894 RFC 2044 RFC 2077 RFC 2110 RFC 2112 RFC 2159 RFC 2183 and 161 more

Actions taken to reduce the impact or severity of a problem. In DDoS context, mitigation refers to techniques and systems used to detect, filter, and stop attack traffic while allowing legitimate traffic through.

Used in RFC 9132 RFC 9387

An attack on an OAuth client that talks to several authorization servers, where the attacker tricks the client about which server is responding so that it sends an authorization code or access token to the attacker.

Plain language An attack where an OAuth client mistakenly sends authentication tokens to the wrong server.

Used in RFC 9207 RFC 9700

A way of splitting a page into a mask layer plus foreground and background layers, so that each part can use the compression method and resolution that suit it best.

Plain language A technique splitting content into layers so each can be compressed according to its type.

Used in RFC 2879 RFC 3949

A function, such as a hash or a block cipher, that combines several inputs so each output bit depends in a complex way on all input bits. It can hide weak or guessable inputs among good ones, but it cannot make more unpredictability than went in.

Plain language A function that combines inputs so the output depends on all of them equally.

Used in RFC 1750 RFC 4086 RFC 6366 RFC 7693

Master Key Identifier. An optional field in an SRTP packet that tells the receiver which master key was used, which makes re-keying easy.

Plain language An identifier in encrypted packets indicating which key to use for decryption.

Used in RFC 3711 RFC 4383 RFC 4568 RFC 5764 RFC 7714

The IKEv2 Mobility and Multihoming protocol, which lets IPsec Security Associations move between IP addresses when a device changes networks.

Used in RFC 4555 RFC 9329

In Proxy Mobile IPv6, the entity that detects a mobile node's attachment and provides it with IP connectivity.

Plain language A gateway that detects mobile device attachment and assigns network connectivity.

Used in RFC 4830 RFC 4831 RFC 4832 RFC 5213 RFC 5779 RFC 5844 RFC 5845 RFC 5846 RFC 5847 RFC 5949 RFC 6097 RFC 6279 RFC 6463 RFC 6572 RFC 6602 RFC 6705 RFC 6757 RFC 6909 RFC 7028 RFC 7222 RFC 7389 RFC 7563 RFC 7864 RFC 8191

A device that moves between network subnets and requires its IP traffic to be redirected as it moves, typically handled by mobility protocols like Mobile IPv4 or Mobile IPv6.

Plain language A device that maintains connectivity while moving between different networks.

Used in RFC 2520 RFC 3374

A protocol that lets a mobile device keep its IP address while roaming between different networks, by using tunneling and home agents to redirect traffic.

Plain language A protocol allowing devices to keep the same IP address while moving to different networks.

Used in RFC 2002 RFC 2004 RFC 2290 RFC 2356 RFC 2794 RFC 3024 RFC 3025 RFC 3115 RFC 3132 RFC 3374 RFC 3519 RFC 4093 RFC 4163 RFC 4830 RFC 4957 RFC 5177 RFC 5944 RFC 5980

A protocol allowing IPv4 devices to move between networks while maintaining the same IP address and remaining reachable through a Home Agent.

Plain language A protocol for IPv4 devices to maintain the same address while roaming between networks.

Used in RFC 3957 RFC 4093 RFC 4332 RFC 4636 RFC 5944

A protocol where a mobile node keeps a home address and registers its current location with a home agent, so it stays reachable when it moves away from its home link.

Plain language A protocol for IPv6 devices to keep their home address and remain reachable while moving.

Used in RFC 3724 RFC 4260 RFC 4283 RFC 4830 RFC 5149 RFC 5380 RFC 5720 RFC 5757 RFC 5778 RFC 5845 RFC 6088 RFC 6089 RFC 6496 RFC 7109

An IPv6 prefix delegated to a Mobile Router and advertised in the Mobile Network. A Mobile Network can have more than one.

Plain language An IPv6 address prefix assigned to a moving network and shared by all devices in it.

Used in RFC 3963 RFC 4885 RFC 4887 RFC 4980

A device that moves between networks in Mobile IPv4 while maintaining a single home IP address and connectivity.

Plain language A device that moves between networks while maintaining its home address.

Used in RFC 2002 RFC 2290 RFC 2794 RFC 3024 RFC 3115 RFC 3344 RFC 3957 RFC 4004 RFC 4283 RFC 4332 RFC 4636 RFC 4640 RFC 4721 RFC 4830 RFC 4832 RFC 4877 RFC 4968 RFC 5149 RFC 5177 RFC 5213 RFC 5380 RFC 5447 RFC 5555 RFC 5568 and 9 more

A router inside a moving network (aircraft or spacecraft) that manages connectivity for all devices in that network.

Plain language A router in a moving network that manages connectivity for all devices aboard.

Used in RFC 3963 RFC 4885 RFC 4886 RFC 4887 RFC 4888 RFC 4889 RFC 4980 RFC 5177 RFC 5522 RFC 6276

The ability of devices to remain connected and functional while moving between networks or changing their point of attachment.

Plain language The ability of devices to remain connected while moving between different networks.

Used in RFC 4135 RFC 7476 RFC 8046 RFC 9063

Either a home agent or a foreign agent in Mobile IPv4. Mobility agents provide the services that keep a mobile node reachable while it moves.

Used in RFC 2002 RFC 3543 RFC 3957

A router in a visited network that acts as a local home agent for mobile nodes. It tracks their current addresses so that movements inside its domain can be handled locally.

Plain language A router tracking mobile device locations and handling local mobility within its domain.

Used in RFC 4140 RFC 5380 RFC 6089

The association of a mobile node's home address with a care-of address, along with the remaining lifetime of that association.

Plain language A record linking a mobile device's home address to its current location and lifetime.

Used in RFC 2002 RFC 2107 RFC 3344 RFC 4830 RFC 5944

A fixed, agreed-upon prime number and generator used for Diffie-Hellman arithmetic modulo that prime. Its size in bits largely determines how strong the key exchange is.

Plain language A set of mathematical values used in key exchanges to establish shared encryption keys.

Used in RFC 5114 RFC 8247 RFC 8268 RFC 9142

A standard container format used in the transmission and storage of multimedia data. It is widely carried over RTP in IPTV systems.

Plain language A standard format for packaging video and audio into small units for transmission.

Used in RFC 2250 RFC 4259 RFC 4326 RFC 6990

Multiprotocol Label Switching: a technique that forwards packets using short labels carried in a label stack instead of looking up a network-layer address at every hop. Architecture in RFC 3031.

Plain language A forwarding method using short labels instead of looking up full network addresses.

Used in RFC 2105 RFC 2209 RFC 2430 RFC 2475 RFC 2547 RFC 2549 RFC 2682 RFC 2702 RFC 2764 RFC 2917 RFC 2998 RFC 3031 RFC 3032 RFC 3033 RFC 3034 RFC 3035 RFC 3036 RFC 3037 RFC 3038 RFC 3063 RFC 3107 RFC 3140 RFC 3209 RFC 3210 and 730 more

A profile of MPLS developed jointly by the IETF and ITU-T to support the capabilities and functionality of a packet transport network.

Plain language A version of MPLS designed for reliable packet transport like telephone networks.

Used in RFC 3812 RFC 5317 RFC 5704 RFC 5950 RFC 6215 RFC 6371 RFC 6426 RFC 6689 RFC 6780 RFC 7054 RFC 7062 RFC 7110 RFC 7439 RFC 7551 RFC 8372

Maximum Receive Unit. The largest Information field, including padding, that a PPP end can receive. The default is 1500 octets and it can be changed by LCP negotiation.

Plain language The largest message size a device can receive in a single transmission.

Used in RFC 1172 RFC 1331 RFC 1471 RFC 1548 RFC 1598 RFC 1638 RFC 1661 RFC 1962 RFC 1967 RFC 1968 RFC 1973 RFC 1974 RFC 1979 RFC 1990 RFC 2118 RFC 2363 RFC 2364 RFC 2419 RFC 2516 RFC 9174

A fully meshed set of MSDP peers that accept each other's SA messages without a peer-RPF check and do not flood them onward within the group. It reduces SA traffic.

Used in RFC 2973 RFC 4611

The Message Session Relay Protocol, which sends a series of instant messages inside a session that two endpoints set up with SIP and SDP.

Plain language A protocol for sending instant messages within a multimedia session.

Used in RFC 5547 RFC 6135 RFC 6714 RFC 7573 RFC 7701 RFC 7702 RFC 7977 RFC 8591 RFC 8873

A policy mechanism that lets a mail domain publish which MX hostnames are acceptable and that TLS should be used. Senders can use it to validate the server name.

Plain language A policy allowing mail domains to specify which servers to use and require encryption.

Used in RFC 8460 RFC 8689

The largest packet, measured in bytes, that a particular network link can carry in one piece. Ethernet's is 1500 bytes. In RFC 1191 the size counts the IP header and data but not lower-level headers.

Plain language The largest packet size a network link can carry, typically 1500 bytes for Ethernet.

Used in RFC 791 RFC 792 RFC 817 RFC 877 RFC 879 RFC 894 RFC 1009 RFC 1042 RFC 1044 RFC 1055 RFC 1063 RFC 1088 RFC 1122 RFC 1132 RFC 1144 RFC 1149 RFC 1188 RFC 1191 RFC 1201 RFC 1209 RFC 1213 RFC 1230 RFC 1242 RFC 1270 and 325 more

An optional non-transitive BGP attribute that a neighbouring AS can set to suggest which of several entry points into its network it would like traffic to use. Lower values are preferred, and values are only compared between routes from the same neighbouring AS.

Plain language A BGP attribute suggesting which network entry point a neighbor prefers for incoming traffic.

Used in RFC 1745 RFC 1773 RFC 3345 RFC 4271 RFC 4451 RFC 5004 RFC 5065 RFC 7311 RFC 7947 RFC 9026

Having more than one IP address on an endpoint. SCTP monitors the paths with heartbeats and moves traffic to another address if the primary path fails.

Plain language Multiple IP addresses on one endpoint for redundancy when a path fails.

Used in RFC 799 RFC 878 RFC 940 RFC 946 RFC 1930 RFC 2181 RFC 2960 RFC 3221 RFC 3286 RFC 3436 RFC 4080 RFC 4165 RFC 4423 RFC 4666 RFC 4960 RFC 5062 RFC 5221 RFC 5658 RFC 6317 RFC 6724 RFC 7291 RFC 7309 RFC 8518 RFC 9063 and 1 more

A pseudowire built from several connected segments that cross intermediate switching provider edge routers between the two terminating routers.

Plain language A virtual connection built from multiple segments connected through intermediate routers.

Used in RFC 5254 RFC 7392

Carrying several independent message streams in one SCTP association, so a lost packet in one stream delays only that stream.

Plain language Multiple independent message streams in one connection, so one loss doesn't block all.

Used in RFC 2960 RFC 3057 RFC 3257 RFC 3286 RFC 3331 RFC 3436 RFC 3758 RFC 3868 RFC 3873 RFC 4165 RFC 4168 RFC 4233 RFC 4960 RFC 5043 RFC 5811 RFC 6083 RFC 6458 RFC 6525 RFC 6526 RFC 7496 RFC 7933 RFC 8260 RFC 8303 RFC 8831 and 1 more

A routing feature that creates several separate topologies, each a subset of the switches and links, out of one physical network. Packets are routed only within the topology they belong to.

Used in RFC 4915 RFC 7722 RFC 8377

Sending one IP datagram to a group of hosts identified by a single class D address, so only members receive it.

Plain language Sending data to a selected group of devices rather than one or all.

Used in RFC 824 RFC 907 RFC 919 RFC 922 RFC 955 RFC 966 RFC 988 RFC 991 RFC 992 RFC 995 RFC 1001 RFC 1022 RFC 1045 RFC 1060 RFC 1062 RFC 1070 RFC 1075 RFC 1088 RFC 1112 RFC 1117 RFC 1126 RFC 1166 RFC 1188 RFC 1201 and 731 more

An IP address in the class D range (224.0.0.0 to 239.255.255.255) that identifies a host group rather than a single host.

Plain language An IP address in the range 224.0.0.0–239.255.255.255 that reaches a group of devices.

Used in RFC 1054 RFC 1060 RFC 1188 RFC 2373 RFC 2375 RFC 2470 RFC 2771 RFC 2909 RFC 3376 RFC 3810 RFC 3918 RFC 4429 RFC 4604 RFC 5309 RFC 5790 RFC 7094 RFC 7341 RFC 7731

A set of network links and routers under unified multicast control, surrounded by border routers that speak both internal and inter-domain multicast protocols.

Used in RFC 3913 RFC 6037

A set of hosts identified by a multicast IP address (224.0.0.0/4 in IPv4, ff00::/8 in IPv6) that receive the same data stream sent to that address.

Plain language A set of devices that receive the same data stream sent to a multicast address.

Used in RFC 1060 RFC 2201 RFC 2432 RFC 3376 RFC 3488 RFC 3918 RFC 4045 RFC 5790 RFC 8966

A protocol that allows IPv6 hosts to report their multicast group memberships to neighboring routers.

Plain language A protocol for IPv6 devices to report which multicast groups they want to receive.

Used in RFC 3590 RFC 3738 RFC 3810 RFC 4604 RFC 4605 RFC 5186 RFC 5757 RFC 5790 RFC 6285 RFC 7028 RFC 7411 RFC 8652 RFC 9166 RFC 9398

A protocol (MLD in IPv6) that allows hosts to notify routers that they wish to receive multicast packets for a particular group address.

Plain language A protocol for devices to request multicast packets from a specific group.

Used in RFC 3810 RFC 5757 RFC 7450 RFC 9279

A router that forwards multicast datagrams between networks and uses IGMP queries to learn which groups have members on each attached network.

Plain language A router that forwards multicast packets between networks and tracks group membership.

Used in RFC 1112 RFC 2022 RFC 2191 RFC 2236 RFC 2365 RFC 2710 RFC 2887 RFC 2934 RFC 3376 RFC 3488 RFC 3569 RFC 3618 RFC 3810 RFC 3973 RFC 4286 RFC 4541 RFC 4601 RFC 4604 RFC 4605 RFC 4608 RFC 4610 RFC 4624 RFC 5059 RFC 5060 and 36 more

The process of forwarding packets from a single source to multiple receivers, using routing protocols that build multicast distribution trees across a network.

Plain language Forwarding a single packet from one source to multiple destinations simultaneously.

Used in RFC 2201 RFC 2909 RFC 3810 RFC 3973 RFC 4609 RFC 4610 RFC 5132 RFC 6037 RFC 6754 RFC 7910 RFC 8279

A 4-bit value in an IPv6 multicast address that limits how far packets sent to that group may travel. Examples are Link-Local, Site-Local and Global.

Plain language A limit on how far multicast packets can travel, from link-local to global.

Used in RFC 2373 RFC 2375 RFC 3559 RFC 3973 RFC 5132 RFC 6308 RFC 7346

A protocol in which RPs tell their peers which multicast sources are active, using Source Active messages. It keeps multiple RPs consistent about active sources.

Plain language A protocol where multicast distribution points inform each other of active sources.

Used in RFC 3446 RFC 4610 RFC 9081

Connecting a network to more than one service provider, usually for reliability. It makes the site harder to aggregate into any one provider's route.

Plain language Connecting to multiple internet service providers for reliability and performance.

Used in RFC 1519 RFC 1629 RFC 1772 RFC 1787 RFC 1998 RFC 2050 RFC 2071 RFC 2260 RFC 2772 RFC 2874 RFC 3056 RFC 3111 RFC 3178 RFC 3257 RFC 3554 RFC 3704 RFC 3873 RFC 4057 RFC 4116 RFC 4168 RFC 4191 RFC 4218 RFC 4219 RFC 4555 and 103 more

An extension of PPP that splits packets into numbered fragments using begin and end bits and a sequence number, so they can be sent and reassembled at the other end.

Plain language An extension that splits packets into numbered fragments for transmission and reassembly.

Used in RFC 1331 RFC 1663 RFC 1974 RFC 1979 RFC 2686 RFC 2687 RFC 2866 RFC 3544

A string chosen by the sender, 1 to 70 characters long, that separates the parts of a multipart body. Each delimiter line is two hyphens plus the boundary, and the last has two extra hyphens.

Plain language A text string separating different parts in a multipart message.

Used in RFC 1341 RFC 1563 RFC 1740 RFC 1820 RFC 1847 RFC 1848 RFC 1873 RFC 1892 RFC 2046 RFC 2049 RFC 2112 RFC 2183 RFC 2387 RFC 2392 RFC 2557 RFC 2848 RFC 3156 RFC 3801 RFC 5621 RFC 5703 RFC 6522 RFC 7578 RFC 7852 RFC 8058 and 3 more

A MIME type with two parts: the first holds the content that was signed, and the second holds a detached signature object. A reader without S/MIME software can still read the message.

Plain language A two-part message where the text stays readable and the signature sits beside it.

Used in RFC 2633 RFC 5751

A modified version of TCP that supports the simultaneous use of multiple paths between two hosts. It presents one TCP-like connection to the application.

Plain language A version of TCP using multiple paths simultaneously between two hosts.

Used in RFC 6182 RFC 6897 RFC 7430 RFC 7556 RFC 8041 RFC 8303

An extension to TCP that lets a single connection use several IP addresses and network paths at once, each path carrying a subflow of the same session.

Used in RFC 7430 RFC 8684

Sharing one connection among several independent streams by labeling each piece of data with the stream it belongs to. SSH uses channel numbers for this.

Plain language Carrying multiple independent data streams in one connection by labeling each piece.

Used in RFC 7 RFC 8 RFC 9 RFC 793 RFC 814 RFC 817 RFC 905 RFC 907 RFC 928 RFC 1008 RFC 1270 RFC 1356 RFC 1547 RFC 1661 RFC 1692 RFC 1795 RFC 1859 RFC 1989 RFC 1990 RFC 2115 RFC 2341 RFC 2371 RFC 2427 RFC 3080 and 49 more

A device that connects two or more endpoints into one multimedia conference. It can mix, switch or compose the media it receives before sending it on.

Plain language A device connecting multiple participants into one multimedia conference.

Used in RFC 7205 RFC 7667 RFC 8845 RFC 8847

Extensions to LDP, also called mLDP, for creating point-to-multipoint and multipoint-to-multipoint label switched paths.

Plain language An extension for building branching paths in multicast label switching.

Used in RFC 6512 RFC 6826 RFC 7246

A neighbor selected by an OLSRv2 router to forward its flooded messages, or to be used for routing. Choosing a limited set of relays reduces the number of retransmissions needed.

Plain language A selected neighbor that forwards messages to reduce retransmissions.

Used in RFC 3626 RFC 5449 RFC 7181 RFC 7184 RFC 7185 RFC 7722

An exchange in which both ends prove their identity to each other, rather than only one side proving itself to the other.

Plain language Both parties proving their identity to each other rather than one-way.

Used in RFC 1411 RFC 1507 RFC 2716 RFC 2759 RFC 4187 RFC 4582 RFC 4746 RFC 4764 RFC 5355 RFC 5418 RFC 5734 RFC 6546 RFC 8120 RFC 8125 RFC 9887

A multicast VPN: a BGP/MPLS IP VPN that also carries multicast traffic between customer sites. Provider Edge routers exchange customer multicast routing information using either PIM or BGP.

Plain language A private network that carries multicast traffic between multiple customer sites.

Used in RFC 6513 RFC 6517 RFC 6625 RFC 7431 RFC 7900 RFC 8503 RFC 8534 RFC 9573

A DNS resource record naming a mail exchanger for a domain, with a preference value used to rank which to try first.

Plain language A DNS record directing email for a domain to a mail server.

Used in RFC 821 RFC 883 RFC 974 RFC 1031 RFC 1033 RFC 1123 RFC 1183 RFC 1211 RFC 1279 RFC 1383 RFC 1386 RFC 1480 RFC 1530 RFC 1537 RFC 1569 RFC 1703 RFC 1713 RFC 1846 RFC 1912 RFC 1985 RFC 2142 RFC 2151 RFC 2163 RFC 2181 and 27 more