T

An ITU-T standard that defines how text conversation sessions work, including how to encode text, control elements, and handle character sequences.

Plain language An ITU-T standard defining how text conversation sessions work, including encoding and character handling.

Used in RFC 2793 RFC 4103

An ITU-T international standard that defines procedures for sending real-time facsimile (fax) documents between Group 3 fax machines over IP networks, using either TCP or UDP as the transport protocol.

Plain language An ITU-T standard for sending fax documents in real-time over IP networks using TCP or UDP.

Used in RFC 3362 RFC 4734 RFC 5347

A protocol for authentication, authorization and accounting (AAA) used to administer routers, network access servers and similar devices from central servers.

Plain language A protocol for authentication, authorization and accounting on routers and network access servers.

Used in RFC 4778 RFC 9887 RFC 9950

A way of packing data as a code (the tag), a count of bytes (the length) and then the bytes themselves (the value). A reader can skip any item it does not understand by using the length.

Plain language A data format where each field is labeled with its type, length and value so readers can skip unknown items.

Used in RFC 1395 RFC 2131 RFC 2132 RFC 2516 RFC 2868 RFC 2910 RFC 3212 RFC 3331 RFC 3784 RFC 3847 RFC 4171 RFC 4430 RFC 4446 RFC 5061 RFC 5130 RFC 5410 RFC 5857 RFC 6320 RFC 6395 RFC 6839 RFC 7035 RFC 7271 RFC 7401 RFC 7552 and 32 more

A queue management discipline that accepts packets until a maximum queue length is reached and then drops each newly arriving packet until the queue has room again.

Plain language A queue management method that drops new packets when the queue reaches maximum capacity.

Used in RFC 2309 RFC 5562 RFC 7567 RFC 8033 RFC 8289 RFC 8311 RFC 8867 RFC 8869

The ordered list of targeted field names a cache uses for its caching policy, from most to least applicable. The cache uses the first listed field that is valid and non-empty.

Plain language An ordered list of fields a cache checks for its caching policy, using the first valid non-empty field.

Used in RFC 4914 RFC 9213

The Transmission Control Protocol. It provides a reliable, ordered, full-duplex byte stream between two programs on top of IP, using sequence numbers, acknowledgments, retransmission and a window.

Plain language A protocol providing reliable, ordered delivery of data between two programs using sequence numbers and acknowledgments.

Used in RFC 42 RFC 60 RFC 87 RFC 238 RFC 270 RFC 298 RFC 661 RFC 675 RFC 761 RFC 766 RFC 771 RFC 772 RFC 773 RFC 774 RFC 776 RFC 781 RFC 782 RFC 784 RFC 788 RFC 793 RFC 794 RFC 800 RFC 801 RFC 813 and 628 more

A TCP option, defined in RFC 5925, that lets two endpoints authenticate the segments they exchange using shared keys. It replaced the older TCP MD5 signature option.

Used in RFC 5926 RFC 9648

The data structure that holds the state and parameters of a TCP connection, including sequence numbers, window sizes, and connection state. Deleting it terminates the connection.

Plain language The data structure holding the state and parameters of one TCP connection.

Used in RFC 2140 RFC 2452 RFC 9040

A congestion control mechanism that adjusts sending rate more smoothly than TCP does, reducing data loss while maintaining fairness with TCP flows.

Plain language A congestion control mechanism that adjusts sending rate smoothly while maintaining fairness with TCP.

Used in RFC 4336 RFC 4342 RFC 4828

An optional, variable-length field after the fixed TCP header that carries extra information, identified by a kind number and a length. Space for options is limited.

Used in RFC 1323 RFC 2883 RFC 4163 RFC 5690 RFC 5926 RFC 6967 RFC 8548 RFC 8684 RFC 9768

The unit of data TCP sends: a TCP header followed by some bytes of the application's stream, carried inside one IP datagram.

Plain language The unit of data TCP sends: a header and application bytes carried in one IP datagram.

Used in RFC 793 RFC 879 RFC 983 RFC 1323 RFC 1337 RFC 2018 RFC 2351 RFC 2385 RFC 2415 RFC 2416 RFC 2488 RFC 2581 RFC 2647 RFC 2883 RFC 3042 RFC 3390 RFC 3649 RFC 4022 RFC 5044 RFC 5482 RFC 5681 RFC 5926 RFC 5961 RFC 6191 and 16 more

A TCP facility that signals the receiver ahead of the normal flow of data that something special is in the stream. Telnet combines it with the Data Mark command to make the Synch signal.

Plain language A TCP facility signaling the receiver that something special is coming in the data stream.

Used in RFC 764 RFC 793 RFC 854 RFC 1282 RFC 2147 RFC 2675 RFC 4413 RFC 6897 RFC 7414 RFC 7560

A 16-bit number that tells the receiving host which application or conversation a TCP or UDP packet belongs to. NAPT rewrites these numbers to tell sessions apart.

Plain language A 16-bit number identifying which application on a host should receive a TCP or UDP packet.

Used in RFC 783 RFC 854 RFC 1204 RFC 1288 RFC 1340 RFC 1413 RFC 1906 RFC 2722 RFC 2746 RFC 2818 RFC 2940 RFC 3022 RFC 3102 RFC 3195 RFC 3261 RFC 3912 RFC 4171 RFC 4707 RFC 4992 RFC 4993 RFC 5097 RFC 5428 RFC 5440 RFC 5460 and 17 more

A traffic engineering link is a subinterface capable of carrying MPLS traffic engineered traffic. It abstracts the properties of a link for routing and signaling.

Plain language A traffic engineering link capable of carrying MPLS traffic, abstracting properties for routing.

Used in RFC 3945 RFC 4202 RFC 4204 RFC 4207 RFC 4209 RFC 4220 RFC 5150 RFC 5623 RFC 6001

The identifier of an OSPF traffic engineering node, carried in the TE Router Address TLV. It is a stable IP address that is always reachable when there is IP connectivity to the associated node.

Plain language The number that names one transport node in the routing advertisements.

Used in RFC 4990 RFC 6827

A pair of a Class-Type and a preemption priority allowed for that Class-Type. A router can be configured with up to 8 of them.

Plain language A pair of a Class-Type and preemption priority assigned for traffic engineering.

Used in RFC 4124 RFC 4829

Measurements of how a network is behaving, collected by the network itself and sent to a system that analyses them. In IOAM the measurements are taken from packets as they cross the network.

Plain language Measurements of how a network is behaving, collected by the network itself.

Used in RFC 9326 RFC 9387

A kind of video conferencing in which rooms with several cameras, screens and microphones try to make remote participants feel present together.

Plain language Video conferencing using multiple cameras, screens and microphones to make remote participants feel present.

Used in RFC 7205 RFC 7262 RFC 8845 RFC 8846 RFC 8847 RFC 8848

A protocol for remote login that carries a user's keyboard and screen to a command interpreter on another host over one TCP connection.

Plain language A protocol for remote login that carries a user's keyboard and screen over one TCP connection.

Used in RFC 15 RFC 33 RFC 96 RFC 97 RFC 98 RFC 100 RFC 106 RFC 110 RFC 111 RFC 112 RFC 123 RFC 130 RFC 131 RFC 137 RFC 138 RFC 139 RFC 140 RFC 146 RFC 158 RFC 165 RFC 166 RFC 176 RFC 183 RFC 189 and 270 more

An ordered list of field types and lengths that tells a receiver how to read the data records that follow. Each template is identified by a Template ID.

Plain language An ordered list of field types and lengths that tells a receiver how to read the data records that follow.

Used in RFC 5101 RFC 5153 RFC 5470 RFC 5472 RFC 5473 RFC 5477 RFC 6235 RFC 6615 RFC 7011 RFC 7013

A description of the ordered fields that make up a data record. Collectors need it to read the records that follow.

Plain language A description of the ordered fields that make up a data record.

Used in RFC 5101 RFC 5473 RFC 5476 RFC 6313 RFC 7011

Encoding a video stream in layers so that frames of higher layers can be dropped, leaving a lower frame rate that still decodes properly.

Plain language Encoding video in layers so higher layers can be dropped for lower frame rates without breaking.

Used in RFC 7741 RFC 9628

An IPv6 address meant to be used for a short time, to address privacy concerns. It contrasts with a public address, which is stable.

Plain language A short-lived IPv6 address meant for temporary use to address privacy concerns.

Used in RFC 3041 RFC 4941 RFC 6724 RFC 7707 RFC 7721 RFC 8981

A tunneling protocol that lets a node behind one or more IPv4 NATs obtain IPv6 connectivity by carrying IPv6 packets over UDP. It uses Teredo servers as helpers.

Plain language A tunneling protocol letting nodes behind IPv4 NATs obtain IPv6 connectivity over UDP.

Used in RFC 4852 RFC 5902 RFC 5991 RFC 6081

A minimal IPv6 packet with no payload (next header 59) that Teredo clients and relays send to create a mapping in a NAT.

Plain language A minimal IPv6 packet with no payload that creates a mapping in a NAT.

Used in RFC 4380 RFC 6081

A logical entity on a Media Gateway that sources and/or sinks media or control streams, such as a telephone line or an RTP flow. Terminations are placed into Contexts to be connected to each other.

Plain language A logical entity on a Media Gateway that sources or sinks media or control streams.

Used in RFC 2885 RFC 3525

Timed Efficient Stream Loss-tolerant Authentication, a scheme where a sender authenticates packets with keys that are revealed only after a delay. Receivers hold each packet until its key arrives and then check it.

Used in RFC 4383 RFC 5776

A set of inputs and expected outputs used to verify that an implementation of a cryptographic algorithm is correct.

Plain language A set of inputs and expected outputs verifying that a cryptographic implementation is correct.

Used in RFC 2286 RFC 4231 RFC 6229 RFC 8251 RFC 9058 RFC 9106 RFC 9529

A named data type defined once in a MIB module so that many objects, in that module or others, can reuse the same syntax and meaning.

Plain language A named data type defined once in a MIB module so many objects can reuse it.

Used in RFC 1213 RFC 1285 RFC 1441 RFC 1442 RFC 1903 RFC 2465 RFC 2579 RFC 2851 RFC 3291 RFC 3295 RFC 3419 RFC 3592 RFC 3593 RFC 3595 RFC 3705 RFC 3796 RFC 3805 RFC 3808 RFC 3811 RFC 4001 RFC 4181 RFC 4268 RFC 4706 RFC 4780 and 8 more

The Trivial File Transfer Protocol. A very small file-transfer protocol over UDP that is simple enough to fit in a boot ROM, so diskless machines use it to download a boot image.

Plain language A minimal file transfer protocol over UDP for diskless machines to download boot images.

Used in RFC 783 RFC 840 RFC 887 RFC 906 RFC 913 RFC 951 RFC 1123 RFC 1350 RFC 1497 RFC 1782 RFC 1783 RFC 1784 RFC 1785 RFC 2021 RFC 2090 RFC 2132 RFC 2347 RFC 2348 RFC 2349 RFC 3617 RFC 4639 RFC 5859 RFC 5970 RFC 7440

A SIP technique in which one party sets up and controls a media session between other parties, for example connecting a user agent to a transcoder.

Plain language A SIP technique where one party sets up and controls a media session between other parties.

Used in RFC 3725 RFC 3891 RFC 4117 RFC 5369 RFC 5631

A cookie set by a server other than the site the user is visiting, for example by an ad network whose content is embedded in the page. It lets that server recognize the same user across different sites.

Plain language A cookie from a server other than the site visited, allowing that server to recognize users across sites.

Used in RFC 2964 RFC 6265 RFC 6462

The SYN, SYN-ACK, ACK exchange that opens a TCP connection and lets both sides agree on their initial sequence numbers.

Plain language The SYN, SYN-ACK, ACK exchange that opens a TCP connection and agrees on initial sequence numbers.

Used in RFC 675 RFC 761 RFC 793 RFC 827 RFC 908 RFC 916 RFC 964 RFC 1337 RFC 1379 RFC 1948 RFC 2140 RFC 2267 RFC 2678 RFC 3038 RFC 3360 RFC 3373 RFC 3390 RFC 3540 RFC 4101 RFC 4340 RFC 4614 RFC 5303 RFC 5382 RFC 5562 and 22 more

A digital signature scheme where a private key is split into shares, and a minimum number of shares (the threshold) must be combined to create a valid signature.

Plain language A digital signature scheme where a minimum number of private key shares must combine to create a signature.

Used in RFC 5636 RFC 9591

The amount of data a system can handle per unit of time. In device benchmarking it is the highest rate at which no frames are dropped.

Plain language The maximum amount of data a system can process per unit time without dropping frames.

Used in RFC 1242 RFC 1944 RFC 3918 RFC 5166 RFC 5632 RFC 6349 RFC 8216 RFC 8219 RFC 8239 RFC 9411

An encrypted Kerberos credential that a client presents to a service. It contains the client's identity and a session key, sealed in the service's key so the client cannot read or alter it.

Plain language An encrypted Kerberos credential containing the client's identity and session key, readable only by the service.

Used in RFC 1235 RFC 1507 RFC 1731 RFC 1964 RFC 2350 RFC 2712 RFC 2942 RFC 4120 RFC 4121 RFC 4153 RFC 4430 RFC 4537 RFC 4556 RFC 4757 RFC 4777 RFC 5077 RFC 5896 RFC 6043 RFC 6111 RFC 6112 RFC 6113 RFC 6448 RFC 6806 RFC 6880 and 3 more

The ticket a client gets from the Authentication Service at login. It is presented to the Ticket-Granting Service to obtain tickets for other services without using the password again.

Plain language A ticket from the Authentication Service allowing a client to obtain service tickets without reusing the password.

Used in RFC 3820 RFC 4120 RFC 4430 RFC 5896 RFC 6113 RFC 6806 RFC 8070

Tag Image File Format, a file format for storing raster images together with tagged fields that describe them, such as size, resolution and compression.

Plain language A file format for storing raster images with tagged fields describing size, resolution and compression.

Used in RFC 1314 RFC 2306 RFC 2532 RFC 2879 RFC 3949 RFC 3965

The difference between a local time and UTC, written as a sign, hours and minutes such as -08:00, calculated as local time minus UTC.

Plain language The difference between local time and UTC, calculated as local time minus UTC.

Used in RFC 1589 RFC 3339 RFC 4833 RFC 9557 RFC 9636 RFC 9769 RFC 9922

A service that issues a cryptographically secure confirmation, called a timestamp, that certain data existed at a given time.

Plain language A service issuing cryptographically secure confirmation that certain data existed at a given time.

Used in RFC 3126 RFC 4810 RFC 4998 RFC 5126 RFC 5544 RFC 6283 RFC 9921

The length in seconds (X) of the window during which one TOTP value stays the same. RFC 6238 recommends a default of 30 seconds.

Plain language The length in seconds of the window during which one TOTP value remains valid.

Used in RFC 1305 RFC 6238

A way to share one line among several channels by giving each a fixed, repeating time slot. E1 and T1 lines work this way.

Plain language Sharing one line among several channels by giving each a fixed, repeating time slot.

Used in RFC 3471 RFC 3473 RFC 4139 RFC 4202 RFC 4553 RFC 4842 RFC 5086 RFC 5087 RFC 5287 RFC 5611

A set of IEEE 802.1 standards that provide zero congestion loss and bounded latency in bridged networks, so that traffic is delivered predictably.

Plain language IEEE 802.1 standards providing zero congestion loss and bounded latency in bridged networks.

Used in RFC 8655 RFC 9016 RFC 9024

A medium access mode of IEEE 802.15.4 in which time is divided into slots and each transmission happens in a scheduled slot on a scheduled channel offset. Communication follows a schedule of such cells.

Plain language A medium access mode where time is divided into slots and transmissions happen in scheduled cells on scheduled channels.

Used in RFC 8480 RFC 9030

The state in which the endpoint that closed first waits for twice the maximum segment lifetime before deleting a connection, so the final ACK is not lost and stray old segments expire.

Plain language The state where the endpoint that closed first waits for twice the maximum segment lifetime before deleting the connection.

Used in RFC 793 RFC 916 RFC 1270 RFC 1337 RFC 1379 RFC 1644 RFC 3102 RFC 4340 RFC 5382 RFC 6056 RFC 6191 RFC 6269 RFC 7413 RFC 9210 RFC 9293

An unambiguous written representation of one instant in time, as used to record when a protocol event happened.

Plain language An unambiguous written representation of one instant in time marking when a protocol event happened.

Used in RFC 28 RFC 32 RFC 34 RFC 41 RFC 738 RFC 868 RFC 1057 RFC 1071 RFC 1128 RFC 1165 RFC 1323 RFC 1361 RFC 1507 RFC 1510 RFC 1761 RFC 1769 RFC 1889 RFC 1890 RFC 2006 RFC 2029 RFC 2198 RFC 2250 RFC 2330 RFC 2435 and 137 more

Terminal Interface Processor; specialized hardware that allowed user terminals to connect directly to the ARPANET without an intermediate host computer.

Plain language Specialized hardware that allowed terminals to connect directly to the ARPANET.

Used in RFC 283 RFC 321 RFC 622 RFC 5546

The protocol that encrypts and authenticates a connection between two programs, most visibly in HTTPS. RFC 6066 works with version 1.2, defined in RFC 5246.

Plain language A protocol that encrypts and authenticates a connection between two programs, used in HTTPS.

Used in RFC 2179 RFC 2222 RFC 2246 RFC 2255 RFC 2316 RFC 2371 RFC 2487 RFC 2565 RFC 2566 RFC 2567 RFC 2568 RFC 2595 RFC 2653 RFC 2712 RFC 2716 RFC 2719 RFC 2728 RFC 2748 RFC 2801 RFC 2813 RFC 2817 RFC 2818 RFC 2829 RFC 2830 and 635 more

A way to derive extra keying values from a TLS connection using a label, so that applications can bind their own data to that specific connection.

Used in RFC 8915 RFC 9261 RFC 9266 RFC 9427 RFC 9930

An optional block of data added to the client hello or server hello to offer or accept an extra feature. Peers that do not know an extension ignore it.

Plain language An optional block of data in the client or server hello offering or accepting an extra TLS feature.

Used in RFC 2487 RFC 4366 RFC 4492 RFC 4642 RFC 4680 RFC 4681 RFC 5019 RFC 5054 RFC 5077 RFC 5705 RFC 5746 RFC 5764 RFC 5878 RFC 6042 RFC 6066 RFC 6091 RFC 6176 RFC 6460 RFC 6520 RFC 6962 RFC 7151 RFC 7250 RFC 7301 RFC 7366 and 31 more

The opening exchange in which a TLS client and server agree on settings, check certificates and set up keys before any application data is sent.

Plain language The opening exchange where TLS peers agree on settings, verify certificates and set up encryption keys.

Used in RFC 2246 RFC 2712 RFC 2716 RFC 2817 RFC 2830 RFC 3207 RFC 3436 RFC 3546 RFC 3943 RFC 4217 RFC 4261 RFC 4279 RFC 4346 RFC 4347 RFC 4366 RFC 4492 RFC 4507 RFC 4572 RFC 4642 RFC 4680 RFC 4681 RFC 4851 RFC 5054 RFC 5077 and 65 more

A DNS record type that ties a TLS server's certificate or public key to its service name. It carries a certificate usage, a selector, a matching type and the certificate association data.

Plain language A DNS record tying a TLS server's certificate or public key to its service name.

Used in RFC 6698 RFC 7671 RFC 7672

A Type-Length-Value element, a common way to pack data in a protocol message. A sub-TLV is a TLV nested inside another.

Plain language A Type-Length-Value element, a common way to pack data in protocol messages.

Used in RFC 3103 RFC 3359 RFC 3472 RFC 3475 RFC 3476 RFC 3630 RFC 3784 RFC 3787 RFC 4547 RFC 4582 RFC 4970 RFC 4972 RFC 5029 RFC 5036 RFC 5073 RFC 5089 RFC 5120 RFC 5252 RFC 5301 RFC 5302 RFC 5303 RFC 5304 RFC 5305 RFC 5307 and 115 more

A rate-limiting method that adds tokens to a bucket at a steady rate and spends one per message. It allows short bursts up to the bucket size while keeping the long-term average under the limit, and RFC 4443 recommends it for ICMPv6 errors.

Plain language A rate-limiting method adding tokens at a steady rate and spending one per message.

Used in RFC 1363 RFC 1633 RFC 2206 RFC 2210 RFC 2211 RFC 2212 RFC 2215 RFC 2381 RFC 2430 RFC 2475 RFC 2597 RFC 2638 RFC 2688 RFC 2697 RFC 2698 RFC 2724 RFC 2963 RFC 2990 RFC 2996 RFC 3006 RFC 3175 RFC 3208 RFC 3212 RFC 3246 and 17 more

The act of asking an OAuth 2.0 authorization server about the current state of a token, such as whether it is active and what it allows. It is done by calling the server's introspection endpoint.

Plain language Asking an OAuth 2.0 server about the current state of a token, such as whether it is active.

Used in RFC 7662 RFC 8707 RFC 9200 RFC 9767

A local network technology (IEEE 802.5) in which a station may transmit only while it holds a token. The maximum frame size is set by how long a node may hold the token.

Plain language A local network technology where stations transmit only while holding a token.

Used in RFC 1513 RFC 1748 RFC 1749 RFC 2470 RFC 2816

The rightmost part of a domain name, such as .COM, .ORG, .UK, or .FR. Top-level domains are either generic (gTLDs like .COM) or country-code domains (ccTLDs like .UK).

Plain language The rightmost part of a domain name, such as .com or .org.

Used in RFC 2240 RFC 4185

The highest level in the domain name hierarchy, such as .com, .org, or .edu in the Domain Name System.

Plain language The highest level in the domain name hierarchy, such as .com or .org.

Used in RFC 819 RFC 920 RFC 1031 RFC 2146 RFC 2352 RFC 2664 RFC 3375 RFC 4713 RFC 4931 RFC 6761 RFC 7485 RFC 7489 RFC 8023 RFC 8244

Time-Based One-Time Password. An algorithm, defined in RFC 6238, that turns a shared secret and the current time into a short numeric code that is valid for only a brief window, usually 30 seconds.

Plain language A time-based algorithm that turns a shared secret and current time into a short numeric code valid for about 30 seconds.

Used in RFC 6030 RFC 6238 RFC 6560 RFC 7894 RFC 8176

A small header that wraps one ISO transport message so it can be sent over a TCP byte stream. It carries a version number and the total length of the packet.

Plain language A small header wrapping one ISO transport message for sending over a TCP byte stream.

Used in RFC 1006 RFC 1859

A tool that discovers the path to a host by sending datagrams with small time-to-live values and listening for the ICMP Time Exceeded messages that gateways send back.

Plain language A tool discovering the path to a host by sending datagrams with small TTL values.

Used in RFC 791 RFC 792 RFC 1470 RFC 1574 RFC 1578 RFC 1739 RFC 1879 RFC 2004 RFC 2151 RFC 2745 RFC 2925 RFC 2991 RFC 3542 RFC 3609 RFC 4379 RFC 4560 RFC 4884 RFC 4950 RFC 5388 RFC 5508 RFC 5837 RFC 5884 RFC 6045 RFC 6274 and 42 more

A directed path from a source node to one or more destinations across a wireless network, with cells and buffers reserved at each hop. It gives a guaranteed latency to well-characterized flows.

Used in RFC 9030 RFC 9914

A directory service that keeps a list of the peers taking part in a particular channel or file distribution and hands out lists of them on request. It does not carry the content itself.

Used in RFC 5594 RFC 5694 RFC 6972 RFC 7846

Inferring information from observed traffic flows, such as presence, amount, direction, timing and packet size, even when the flows are encrypted.

Used in RFC 1825 RFC 6562 RFC 6973 RFC 7908

An 8-bit IPv6 header field used to identify and distinguish classes or priorities of packets.

Plain language An 8-bit IPv6 header field identifying the priority or class of a packet.

Used in RFC 1455 RFC 2123 RFC 2430 RFC 2460 RFC 2514 RFC 2597 RFC 2638 RFC 2751 RFC 2814 RFC 2815 RFC 2816 RFC 2836 RFC 2859 RFC 3168 RFC 3290 RFC 3334 RFC 3542 RFC 3564 RFC 3644 RFC 4127 RFC 4363 RFC 4689 RFC 5316 RFC 5455 and 35 more

The process of classifying, metering, marking, shaping, and policing traffic at a router to enforce traffic profiles and service-level agreements.

Plain language Classifying, metering, marking, shaping and policing traffic to enforce service agreements.

Used in RFC 2475 RFC 2990 RFC 3213 RFC 3247 RFC 3290 RFC 3292 RFC 4182 RFC 9956

A named set of ATM traffic parameters, such as a peak cell rate, that describes how a connection should behave. Descriptors are held in the traffic descriptor parameter table and referenced by virtual link tables.

Plain language A saved set of traffic settings, such as a peak rate, that connections can point at instead of repeating the numbers.

Used in RFC 2331 RFC 2515 RFC 2761

The symmetric key used to encrypt and decrypt group data traffic (for example, IPsec ESP packets), distributed by the GCKS to all group members.

Plain language The symmetric key distributed by GCKS to group members for encrypting group data traffic.

Used in RFC 3083 RFC 4131 RFC 6407 RFC 9838

Steering traffic along chosen paths through a network, using information such as link bandwidth, instead of only taking the shortest route.

Plain language Steering traffic along chosen paths through a network instead of only taking the shortest route.

Used in RFC 2340 RFC 2430 RFC 2702 RFC 3209 RFC 3210 RFC 3213 RFC 3272 RFC 3471 RFC 3473 RFC 3564 RFC 3630 RFC 3784 RFC 3812 RFC 3906 RFC 3970 RFC 4090 RFC 4124 RFC 4128 RFC 4190 RFC 4206 RFC 4207 RFC 4216 RFC 4655 RFC 4929 and 56 more

The collection of all traffic engineering information about the nodes and links in a network, used as the basis for computing TE paths.

Plain language The collection of traffic engineering information about nodes and links used for computing TE paths.

Used in RFC 4655 RFC 5152 RFC 5623 RFC 5671 RFC 6825 RFC 7399 RFC 8233 RFC 8413 RFC 8426 RFC 8795 RFC 9730

A sequence of packets sharing the same source and destination addresses at one or more layers of the network stack, identified for the purpose of measurement and accounting.

Plain language A sequence of packets with the same source and destination addresses identified for measurement.

Used in RFC 2063 RFC 2064 RFC 2475 RFC 2720 RFC 2721 RFC 2722 RFC 2723

Hiding the size and frequency of traffic so that observers cannot learn information from its patterns, even though the data is already encrypted.

Plain language Hiding the size and frequency of traffic so observers cannot learn from its patterns.

Used in RFC 4303 RFC 9347

A description of which packets a Child SA applies to: an address range, a port range and an IP protocol. IKE exchanges them as TSi and TSr payloads.

Plain language A description of which packets a Child SA applies to, including address, port and protocol ranges.

Used in RFC 2401 RFC 4301 RFC 4306 RFC 4555 RFC 4877 RFC 5324 RFC 5406 RFC 5660 RFC 6088 RFC 6089 RFC 7222 RFC 7296 RFC 7619 RFC 7674 RFC 7815 RFC 9061 RFC 9478 RFC 9611 RFC 10053

A traffic management function that smooths bursty traffic by buffering packets and controlling the output rate to match a configured limit.

Plain language Buffering packets and controlling output rate to smooth traffic and match a configured limit.

Used in RFC 2475 RFC 2761 RFC 4115 RFC 7640

An aggregate of traffic flows of the same class that is placed inside a label switched path. It is unidirectional and routable, and it can be moved from one path to another.

Used in RFC 2430 RFC 2702

Consistently selecting a packet at either all measurement points along its path or none of them. This lets a collector rebuild the route the packet took.

Plain language Selecting the same packet at all measurement points along its path to rebuild the route.

Used in RFC 5474 RFC 5475

A random number a client puts in a request so it can match the reply to it. In BOOTP the client discards replies whose transaction ID does not match its own.

Plain language A random number a client puts in a request to match replies to it.

Used in RFC 951 RFC 1002 RFC 1050 RFC 1831 RFC 2297 RFC 2371 RFC 2372 RFC 2741 RFC 3435 RFC 3860 RFC 4582 RFC 4993 RFC 5389 RFC 5452 RFC 6926 RFC 6977 RFC 7653 RFC 7675 RFC 7846 RFC 7877 RFC 7878 RFC 7982 RFC 8505 RFC 9811 and 1 more

The process of converting audio or video from one codec to another, which typically degrades quality and adds latency.

Plain language Converting audio or video from one codec to another, typically reducing quality and adding latency.

Used in RFC 3351 RFC 4348 RFC 5259 RFC 5369 RFC 5631 RFC 7875

A human or automated intermediary acting as a third party in a communication session, converting one type of media stream to another (for example, voice to text or text to video of sign language).

Plain language A human or automated intermediary converting one type of media stream to another.

Used in RFC 3351 RFC 4117 RFC 5369

A hash of all the handshake messages exchanged so far. TLS 1.3 mixes it into key derivation and the Finished message so that tampering is detected.

Plain language A hash of all handshake messages exchanged so far, used in TLS to detect tampering.

Used in RFC 9528 RFC 9588 RFC 9846

In TFTP, the port number each end picks for the duration of one transfer. The two TIDs are used as the UDP source and destination ports, and a packet with the wrong TID is rejected.

Plain language In TFTP, the port number each end picks for one transfer, used as UDP source and destination ports.

Used in RFC 1350

A public key together with the User IDs and certification signatures that bind names to it, in the form used when a key travels between users. RFC 9580 also calls it a certificate.

Plain language The public key, the names attached to it, and the signatures vouching for those names, packaged so it can be passed to somebody else.

Used in RFC 7929 RFC 9580

A data object in a protocol specification that distinguishes one protocol object, such as a datagram, interface, endpoint or session, from others of the same type in a given context. It is usually defined as a series of bits and selected dynamically, rather than statically assigned, and has requirements such as uniqueness for a stated period.

Plain language A number a protocol picks at run time to tell one packet, connection or device apart from others of the same kind.

Used in RFC 9414 RFC 9415 RFC 9416

A PTP device that measures how long a PTP event message takes to pass through it and updates the message with a correction for that transit time.

Plain language A PTP device measuring how long a PTP event message takes to pass through it.

Used in RFC 9760 RFC 10030

The combination of an IP address and a port, typically written as (IP address,port). NAT bindings map one transport address to another.

Plain language The combination of an IP address and port, typically written as (IP address, port).

Used in RFC 1705 RFC 5591 RFC 6146

An IPsec mode in which the security header is inserted between the original IP header and the next-layer protocol, so the original IP header is kept.

Plain language An IPsec mode inserting the security header between the original IP header and next-layer protocol.

Used in RFC 2406 RFC 3193 RFC 3788 RFC 4301 RFC 4302 RFC 4303 RFC 5856

An opaque string of octets used in OSI networks to demultiplex incoming data to the correct service or process, analogous to port numbers in TCP/IP.

Plain language An opaque octet string in OSI networks demultiplexing incoming data to the correct service.

Used in RFC 1161 RFC 1283

A connection between an IPFIX Exporter and an IPFIX Collector over which Templates and Data Records are carried. The IPFIX MIB records one row for each, with its protocol, addresses, ports, refresh timers and status.

Plain language One connection from a device that reports traffic to a device that collects it.

Used in RFC 6615 RFC 9223

An extension to STUN that provides a relay server which forwards media traffic when direct paths through NATs are not available.

Plain language An extension to STUN that provides a relay server forwarding media traffic through NATs.

Used in RFC 5245 RFC 5766 RFC 5767 RFC 6062 RFC 6156 RFC 6314 RFC 7350 RFC 7362 RFC 7478 RFC 7983 RFC 8016 RFC 8445 RFC 8825 RFC 8827 RFC 8835 RFC 8840 RFC 9443

An error-handling approach for a malformed BGP UPDATE message, in which the routes in that message are treated as withdrawn instead of resetting the session.

Plain language An error-handling approach treating malformed BGP UPDATE routes as withdrawn instead of resetting.

Used in RFC 7606 RFC 8092

A group of Diffserv classes whose traffic is forwarded together, for example in a single MPLS TC value. It lets a network offer several behaviors without using many TC values.

Plain language A group of Diffserv classes whose traffic is forwarded together with the same behavior.

Used in RFC 5127 RFC 8100

One of the equal-sized time slots inside a higher-order optical container. Smaller signals are multiplexed into one or more of these slots.

Plain language One of the equal-sized time slots inside a higher-order optical container.

Used in RFC 7062 RFC 7096 RFC 7138 RFC 7139

A timer-based method in which nodes share information by repeating it at growing intervals. A node stays quiet when it has already heard enough consistent messages from its neighbors.

Plain language A timer-based method where nodes repeat information at growing intervals, staying quiet when neighbors say the same.

Used in RFC 7731 RFC 7733 RFC 7787 RFC 8036

An extension to ICE that lets candidate gathering and connectivity checks run in parallel, so candidates can be sent a few at a time instead of all at once.

Plain language An extension to ICE letting candidate gathering and connectivity checks run in parallel.

Used in RFC 7362 RFC 8840 RFC 9725

A timer algorithm that spaces out message transmissions and suppresses a message when neighbors already sent consistent ones. RPL uses it to control how often DIO messages are sent.

Plain language A timer algorithm spacing out message transmissions and suppressing messages neighbors already sent.

Used in RFC 6206 RFC 6550 RFC 6687 RFC 6997

A routing update sent soon after a route changes instead of waiting for the next regular timer. RIP rate-limits them to one every 1 to 5 seconds.

Plain language A routing update sent soon after a route changes instead of waiting for the next regular interval.

Used in RFC 1058 RFC 1581 RFC 1582 RFC 1724 RFC 2080 RFC 2091 RFC 2453 RFC 4783

Transparent Interconnection of Lots of Links, a protocol that forwards Ethernet frames between switches using IS-IS link-state routing and a header with a hop count.

Plain language A protocol forwarding Ethernet frames between switches using IS-IS link-state routing with a hop count.

Used in RFC 6439 RFC 7067 RFC 7172 RFC 7174 RFC 7177 RFC 7179 RFC 7357 RFC 7379 RFC 7455 RFC 7782 RFC 7783 RFC 7978 RFC 8139 RFC 8243 RFC 8564

A 16-bit identifier for an RBridge in TRILL. It is used in the ingress and egress fields of the TRILL header.

Plain language A 16-bit identifier for an RBridge in TRILL used in the header's ingress and egress fields.

Used in RFC 6325 RFC 7780 RFC 9183

A cipher that applies the DES algorithm three times, here as encrypt, decrypt, encrypt, using three independent keys. It enlarges the effective key to 168 bits.

Plain language A cipher applying DES three times with three independent keys, enlarging the effective key to 168 bits.

Used in RFC 2420 RFC 3217 RFC 3766 RFC 4772

A time source whose answer agrees with a majority of other sources in NTP's selection algorithm. Sources that disagree are called falsetickers and are not used.

Plain language A time source whose answer agrees with a majority of other sources in NTP's selection algorithm.

Used in RFC 5905

A set of trunks that are traffic engineered as a unit for making connections within or between switching systems. All of the paths in it are interchangeable except where subgrouped.

Plain language A set of trunks traffic engineered as a unit for making connections between switching systems.

Used in RFC 4904 RFC 5140

A situation in which several network addresses are connected to the same server, so a client can reach it over multiple paths.

Plain language Having several network addresses connected to the same server so clients can reach it over multiple paths.

Used in RFC 5661 RFC 7931 RFC 8587 RFC 8881

A configured DNSKEY, or a hash of one, that a validating resolver treats as its starting point for building an authentication chain. It must be obtained by means outside the DNS.

Plain language A configured DNSKEY that a validating resolver treats as the starting point for building an authentication chain.

Used in RFC 1422 RFC 1507 RFC 2065 RFC 2459 RFC 2704 RFC 2906 RFC 3008 RFC 3125 RFC 3280 RFC 3379 RFC 3658 RFC 3779 RFC 3788 RFC 3860 RFC 3971 RFC 4033 RFC 4035 RFC 4108 RFC 4158 RFC 4261 RFC 4431 RFC 4806 RFC 4945 RFC 4986 and 110 more

A small file that tells a relying party where to fetch a trust anchor's CA certificate and which public key to expect, so it can start validating RPKI data.

Plain language A small file telling a relying party where to fetch a trust anchor's CA certificate.

Used in RFC 7115 RFC 8630 RFC 9691

The secure storage on a device that holds its trust anchors, along with related data such as community identifiers and sequence numbers.

Plain language Secure storage on a device holding its trust anchors and related data.

Used in RFC 5934 RFC 6024 RFC 9019

The line around the systems that a service provider owns or controls. Information may flow freely inside it, but private data must be removed before anything crosses to an untrusted party.

Plain language The line around systems a service provider owns or controls.

Used in RFC 3046 RFC 3724 RFC 5451 RFC 5503 RFC 7001 RFC 7601 RFC 8601

A set of SIP nodes that are explicitly trusted by all users and systems within a domain to assert identity and service information. All nodes in a trust domain must agree on service definitions and policies.

Plain language A set of SIP nodes explicitly trusted by all users to assert identity and service information.

Used in RFC 3325 RFC 3838 RFC 5009 RFC 6050 RFC 6567 RFC 7316

Accepting and storing a public key or credential for an identity the first time it is seen, without authenticating it. Later contact is checked against the stored key.

Plain language Accepting and storing a public key for an identity without authenticating it, checking against it later.

Used in RFC 7435 RFC 7469 RFC 8995 RFC 9190

A hardware cryptoprocessor that stores keys that never leave it, holds measurement registers, and signs reports about them. Defined by the Trusted Computing Group.

Plain language A hardware cryptoprocessor storing keys and holding measurement registers that it signs.

Used in RFC 9683 RFC 9684

A part of a network, such as one VPN or the provider core, whose members trust each other and whose security is judged against breaches from outside it.

Plain language A part of a network whose members trust each other and whose security is judged against outside breaches.

Used in RFC 4111 RFC 6941

A way to authenticate DNS messages using a secret key shared by both parties and a keyed hash code. It is defined in RFC 2845.

Plain language A way to authenticate DNS messages using a secret key shared by both parties and a keyed hash code.

Used in RFC 2845 RFC 2931 RFC 3007 RFC 3645 RFC 4635 RFC 4701 RFC 4795 RFC 5625 RFC 8945 RFC 9103

A traffic specification: a description of the traffic a flow will send, given as a token bucket plus a peak rate, a minimum policed unit and a maximum packet size.

Plain language A traffic specification: a description of the traffic a flow will send as a token bucket plus peak rate.

Used in RFC 2211 RFC 2212 RFC 2215 RFC 2746 RFC 3006 RFC 6003

A counter that is decreased at each hop so a packet cannot circulate forever. In IP it is the TTL field (IPv4) or Hop Limit (IPv6); MPLS label stack entries carry their own 8-bit TTL.

Plain language A counter decreased at each hop so a packet cannot circulate forever.

Used in RFC 791 RFC 792 RFC 815 RFC 823 RFC 827 RFC 882 RFC 883 RFC 891 RFC 919 RFC 922 RFC 925 RFC 970 RFC 974 RFC 994 RFC 1002 RFC 1009 RFC 1033 RFC 1034 RFC 1035 RFC 1054 RFC 1060 RFC 1075 RFC 1118 RFC 1122 and 211 more

A mechanism for carrying packets of one protocol through a network using another protocol, by encapsulating them inside packets of the transport protocol.

Plain language A mechanism for carrying packets of one protocol through a network using another protocol.

Used in RFC 1075 RFC 1241 RFC 1853 RFC 1933 RFC 2003 RFC 2341 RFC 2409 RFC 2473 RFC 2784 RFC 2890 RFC 3102 RFC 3970 RFC 3985 RFC 4087 RFC 4110 RFC 4260 RFC 4888 RFC 5579 RFC 5640 RFC 5779 RFC 5944 RFC 5969 RFC 6115 RFC 6275 and 18 more

A service that negotiates and manages tunnels on behalf of clients, determining the tunnel type, endpoints, and configuration based on network conditions.

Used in RFC 3053 RFC 5572

The technique of wrapping packets of one protocol (the payload) inside packets of another protocol (the carrier) to send them across incompatible networks.

Plain language Wrapping packets of one protocol inside packets of another to send across incompatible networks.

Used in RFC 5572 RFC 8014 RFC 9012

An IPsec mode in which the whole original IP packet is protected and wrapped in a new outer IP header. The outer header names the tunnel endpoints.

Plain language An IPsec mode protecting and wrapping the whole original IP packet in a new outer IP header.

Used in RFC 2401 RFC 2402 RFC 2406 RFC 3193 RFC 4301 RFC 4302 RFC 4303 RFC 5374 RFC 5856 RFC 6071

A LISP edge router that encapsulates packets into the tunnel (an ITR) or decapsulates them at the other end (an ETR). Many routers do both and are called xTRs.

Plain language A LISP edge router that encapsulates packets into the tunnel or decapsulates them at the other end.

Used in RFC 6830 RFC 6835 RFC 7215 RFC 7834 RFC 7835 RFC 9300 RFC 9301

A Network Access Server whose client interfaces are tunnelling endpoints in a protocol such as L2TP, rather than modems. Calls arrive as tunnelled sessions instead of on hardware ports, so the device behaves as a virtual NAS.

Plain language A network access server that users reach through a tunnel rather than a phone line.

Used in RFC 2809 RFC 2881

Wrapping one protocol's packets inside another protocol's headers so they can cross a network that does not understand the inner protocol.

Plain language Wrapping one protocol's packets inside another protocol's headers to cross incompatible networks.

Used in RFC 1241 RFC 1621 RFC 2002 RFC 2004 RFC 2290 RFC 2341 RFC 2356 RFC 2764 RFC 2893 RFC 3024 RFC 3068 RFC 3070 RFC 4029 RFC 4170 RFC 4213 RFC 4459 RFC 4852 RFC 5320 RFC 5416 RFC 5512 RFC 5845 RFC 6127 RFC 6180 RFC 6936 and 1 more

The Two-Way Active Measurement Protocol, which measures network performance by sending test packets that a reflector sends back to the sender.

Plain language A protocol measuring network performance by sending test packets that a reflector sends back.

Used in RFC 5618 RFC 6038 RFC 6673 RFC 6812 RFC 7497 RFC 7717 RFC 7750 RFC 7820 RFC 8913 RFC 8972

A protocol for atomic commitment. In phase one every participant is asked to prepare; in phase two the coordinator tells them to commit or abort.

Plain language A protocol for atomic commitment where participants prepare first, then the coordinator tells them to commit or abort.

Used in RFC 2371 RFC 5810

The second octet of the IPv4 header in RFC 791. It holds precedence bits plus delay, throughput and reliability bits that say how the datagram should be treated. It was later redefined as DSCP and ECN.

Plain language The second octet of the IPv4 header holding precedence, delay, throughput and reliability bits.

Used in RFC 791 RFC 1017 RFC 1046 RFC 1060 RFC 1077 RFC 1126 RFC 1245 RFC 1322 RFC 1340 RFC 1455 RFC 1583 RFC 1678 RFC 1700 RFC 2003 RFC 2475 RFC 2676 RFC 2873 RFC 3260 RFC 4323 RFC 4915

A parameterized notion in the IPPM framework representing a class of packets with specific properties like payload size, protocol type, and source/destination addresses.

Plain language A parameterized notion in IPPM representing a class of packets with specific properties.

Used in RFC 2330 RFC 2680 RFC 2681 RFC 3432 RFC 6248 RFC 7497 RFC 8468

A data structure with three parts: a type field identifying the kind of information, a length field for the size of the data, and a value field containing the actual data. TLVs are used in routing protocols to carry variable-length information flexibly.

Plain language A data structure with three parts: a type identifying the information kind, length for size, and value field.

Used in RFC 3786 RFC 4014 RFC 4205

A way to encode an attribute as a type, a length and a value. A parser can skip an attribute it does not recognize by using the length.

Plain language A way to encode an attribute as a type, length and value so parsers can skip unrecognized attributes.

Used in RFC 3036 RFC 4203 RFC 4540 RFC 4851 RFC 5088 RFC 5384 RFC 5444 RFC 5613 RFC 5792 RFC 7455 RFC 8489 RFC 8510 RFC 9930

A method of encoding structured data where each field is preceded by its type identifier and length, allowing flexible and extensible message formats.

Plain language A method encoding structured data where each field is preceded by its type and length.

Used in RFC 4420 RFC 5497 RFC 5578 RFC 5613 RFC 9139