Pseudowire control word. To disable the control word, use the no form of .

Pseudowire control word The design of these fields is chosen so that an MPLS Label Switching Router performing MPLS payload inspection will not confuse a PWE3 payload with RFC 6391 FAT-PW November 2011 In addition to providing an indication of the flow structure for use in ECMP forwarding decisions, the mechanism described in the document may also be used to select flows for distribution over an IEEE 802. The design of these fields is chosen so that an MPLS Label Switching Router performing MPLS payload inspection will not confuse a PWE3 payload with PW encapsulation Control Word CC Type1：VCCV via Control ChannelがMS-PWでも使えれば、 Data Planeの正常性も確認できてよい、が、 MS-PWを構成するTPE、SPE全てがControl Wordをサポートする必要がある。 Control WordはPWの種類によってはMandatoryではないため、 This chapter includes Pseudowire (PW) Status configuration examples. VPLS MAC learning and packet forwarding. Table management. Otherwise, the provider edge routers cannot exchange control messages to negotiate inclusion or exclusion of the control word. Step 15: control-word include. This issue can be avoided by configuring a BGP VPLS edge (VE) router to request that other BGP VE routers insert a control word between the label stack and the MPLS payload. mpls control-word Control-Word Renegotiation by Label Request Message The control-word negotiation mechanism in [RFC4447], Section 6, is updated to add the Label Request message described in this section. However, in the case Introduction The control-word negotiation mechanism specified in [RFC4447], Section 6. These are Ethernet pseudowire (Epipe), ATM N:1 cell mode pseudowires (Apipe vc-types atm-vcc and atm-vpc), and VT pseudowire (Apipe vc-type atm-cell). com Pages Jun 2, 2014 · The control word negotiation results must match. VPLS and Spanning Tree Protocol. [STANDARDS-TRACK] The control-word negotiation mechanism specified in [RFC4447], Section 6. LDP SP-PE TLV helps to achieve the same. If you enable inclusion of the control word, it must be enabled on both ends of the connection for the circuit to work properly. Viewed 423 times The PW set-up protocol determines whether a PW uses a control word. By default, the control word is RFC 4385 PW3 Control Word for Use over an MPLS PSN February 2006 This document specifies how the PW control word is used to distinguish a PW payload from an IP payload carried over an MPLS PSN. Please see the section "C-Bit Handling Procedures" for further explanation. The design of these fields is chosen so that an MPLS Label Switching Router performing MPLS payload inspection will not confuse a PWE3 payload with The pseudowire (PW) encapsulation of Ethernet, as defined in RFC 4448, specifies that the use of the control word (CW) is optional. This feature specifies a mechanism to signal Pseudowire (PW) status messages using a PW associated channel (AC Mar 29, 2017 · In case of Nokia (Alcatel-Lucent) SR OS is PWHE you configure pseudowire in ethernet mode without control-word, because it is not allowed to configure it in such a way (SR1 configuration). Use the Router Alert label for LSP Ping; do not require control word inspection to determine an LSP Ping packet. By default, the control word is disabled. Control-Word Renegotiation by Label Request Message The control-word negotiation mechanism in [RFC4447], Section 6, is updated to add the Label Request message described in this section. , El-Aawar, N. Pseudowires manage encapsulation, timing, order, and other operations in order to make it transparent to users. VCCV provides a control channel that is associated with a pseudowire (PW), as well as the corresponding operations and management functions such as connectivity verification to be used over that control channel. 202. This issue can be avoided by configuring a BGP VPLS PE router to request that other BGP VPLS edge (VE) routers insert a control word between the label stack and the MPLS payload. However, in the case where a If there is a mismatch between the Encaps Type signaled and the one received, the pseudowire is created but with the operationally down state. g. Pad small packets 2. Introduction The control-word negotiation mechanism specified in , Section 6. jin@zte. Attenuate Packet Delay Variation (PDV) Packet networks create latency and more important PDV, also known as jitter. As an example i am sending a simple ping between each node at each side of the VPLS. 3000 10 ge-0/0/3. Pseudowire Control Word Negotiation Mechanism Update . This false positive can cause out-of-order packet delivery over a pseudowire. Note again that this pings the PW part only from one tunnel end point to the other and does not touch to the AC part of the circuit. If the control word is configured using both commands and a PW template, only the control word configured using commands takes effect. A control-word is an optional 4-byte field located between the MPLS label stack and the Layer 2 payload in the pseudowire packet. The control word negotiation results must match. Dec 1, 2023 · Pseudowire Control-Word. •When PWs were first deployed, some equipment of commercial significance was unable to process the Ethernet Control Word. C = 0 No control word present on this PW. Delord, T. Pseudowire control word. This document updates RFC 4447 and RFC 6073 by adding the Label Request message to resolve this control-word negotiation issue for single-segment and multi . MPLS PW Label with TTL == 1). RFC 6723 Title: Update of the Pseudowire Control-Word Negotiation Mechanism Author: L. 4. that is an IP packet is resolved when the Ethernet PW control word is used therefore: This document updates RFC4448 [RFC4448] to state that where both the ingress PE and the egress PE support the Ethernet pseudowire control word, then the CW MUST be used. In case of Inter-AS L2VPN, there will be a minimum of 2 S-PE in between (each from its own AS border). } ge-0/0/4. Control Flags — Control information concerning the pseudowires, see Figure 2 for more information. The control word Configuration Values that existing control word upgrading flow is likely to occur PE1 and PE2 are all 1, the situation that negotiation result is 0 but occur. The patch For aggregated Ethernet and SONET/SDH interfaces only, configure load balancing based on MPLS labels and payload. Only the IPv4 protocol is supported. Sequence numbers are not validated. In the absence of the CW, an Ethernet PW packet can be misidentified as an IP packet by a label switching router (LSR). The encapsulation process places a pseudowire control word in front of the TDM data. Disclosed in the embodiments of the present application are methods for determining a pseudowire control word negotiation mode and a related device, one method comprising: a device on a first end of a pseudowire receives a first message sent by a device on the opposite end, the first message carrying pseudowire control word negotiation modes supported by the device on the opposite end; and on The present invention relates to data communication field, specifically, it is related to a kind of pseudo-wire control word upgrade method. [STANDARDS-TRACK] Mar 8, 2011 · The encapsulations and modes for which the Control Word is currently optional are: defines three Control Channel types for MPLS PW's: Type 1, using the Pseudowire Control Word, Type 2, using the Router Alert Label, and Type 3, using TTL Expiration (e. How to Configure L2VPN Pseudowire Switching. [STANDARDS-TRACK] Oct 2, 2017 · Pseudowire ethernet control word support in scapy. Dec 15, 2023 · Control Word. Example: Device(config-pw-class)# control-word include: Enables the control word. To aid in backwards compatibility, future implementations MUST be able to send and receive frames without the control word present. Therefore existing control word upgrading flow existing defects, it is VPLS service pseudowire VLAN tag processing. Also you terminate VPWS directly at L3 interface, which terminates this segment (it’s possible to attach more than one spoke-sdp). Since the pseudowire is segmented, we need a way to avoid any loop while manually enabling the pseudowire switching functionality in S-PE. The control-word command enables the use of the control word individually on each mesh SDP or spoke SDP. Introduction The control-word negotiation mechanism specified in [RFC4447], Section 6. Key, Ed. As a result of the Control Word being Mandatory, all implementations of the PWE3 encapsulations SHALL follow Section 6. With the control word function, the device can reassemble the packets. However, in the case Feb 9, 2016 · AToM control word processing is not performed at the L2VPN Pseudowire Switching aggregation point. , Rosen, E. The PW control word is described in RFC 4385. The design of these fields is chosen so that an MPLS Label Switching Router performing MPLS payload inspection will not confuse a PWE3 payload with This command enables the setting of the control word bit in the label message. The design of these fields is chosen so that an MPLS Label Switching Router performing MPLS payload inspection will not confuse a PWE3 payload with an IP payload. In most of these encapsulations, use of the Pseudowire (PW) Control Word is required. PW templates simplify the configuration of PWs with similar attributes. 7. When a control word is used, and that CW uses the "Generic PW MPLS Control Word" format (see Section 3 of [RFC4385]), a Control Channel for use of VCCV messages can be created by using the PW Associated Channel CW format (see Section 5 of [RFC4385]). To disable the control word, use the no form of Nov 30, 2011 · vccv {control-word | router-alert | ttl} Example:Router(config-pw-class)# vccv control-word Sets the MPLS pseudowire control channel (CC) type. Pseudowire customizations include following features: Encapsulation type . This document describes the preferred design of a Pseudowire Emulation Edge-to-Edge (PWE3) Control Word to be used over an MPLS packet switched network, and the Pseudowire Associated Channel Header. This document updates RFC 4447 and RFC 6073 by adding the Label Request message to resolve this control-word negotiation issue for single-segment and multi Aug 2, 2019 · Pseudowire customization can be achieved using interface templates and pseudowire interfaces that are applied to L2VPN context members. 2000 20 ge-0/0/1. Heron, “Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP),” April 2006. Sep 6, 2023 · Pseudowires (PW) are used to provide end-to-end services across an MPLS network. , S. 1 of (Martini, L. E in which an ATM attachment circuit is attached. ), ZTE Internet-Draft Raymond Key (ed. , Smith, T. The control-word has the following functions: This document describes the preferred design of a Pseudowire Emulation Edge-to-Edge (PWE3) Control Word to be used over an MPLS packet switched network, and the Pseudowire Associated Channel Header. The renegotiation process begins when the local PE has received the remote Label Mapping message with the C bit set to 0, and at the point its use of control Abstract This document describes the preferred design of a Pseudowire Emulation Edge-to-Edge (PWE3) Control Word to be used over an MPLS packet switched network, and the Pseudowire Associated Channel Header. The control-word command enables the use of the control word individually on each mesh SDP or spoke-SDP. [STANDARDS-TRACK] Introduction The control-word negotiation mechanism specified in [RFC4447], Section 6. 1000 30 Label-base Offset Size Range Preference 800000 1 32 32 100 status-vector: 7F BF EF FB Label-base Offset Size Range Preference 800256 33 4 3 100 status-vector: E0 connection-site Type St Time last up # Up trans 10 rmt Up Jan 17 22:14:28 2021 1 Remote PE Nov 6, 2012 · The only constraint will be the PW label TTL expiry. Control Word The control word has these€five functions:€ 1. control word, then the pseudowire control word should be used. The different PW control plane domains may belong to independent autonomous systems, or the PSN technology is This document defines the behavior of a new type of Multi-Segment Pseudowire (MS-PW) Switching PE (S-PE) which enhances the S-PE functions defined in [RFC 6073], with the capability to switch an Ethernet pseudowire (PW) segment that uses the PW Control Word (CW) [RFC 4385] with an Ethernet PW segment that does not use the CW. The control word carries generic and Layer 2 payload-specific information. [RFC4447] specifies that if both endpoints prefer the use of the control word, then the pseudowire control word should be used. It then describes the preferred design of a PW Control Word to be use over an MPLS PSN, and the Pseudowire Associated Channel Header. (config)# interface pseudowire 100 Router(config-if)# encapsulation mpls The control-word negotiation mechanism specified in RFC 4447 has a problem when a PE (Provider Edge) changes the preference for the use of the control word from NOT PREFERRED to PREFERRED. This document updates RFC The control-word negotiation mechanism specified in RFC 4447 has a problem when a PE (Provider Edge) changes the preference for the use of the control word from NOT PREFERRED to PREFERRED. specifies that if both endpoints prefer the use of the control word, then the pseudowire control word should be used. Layer 2 MTU — Maximum Transmission Unit to be used on the pseudowires. Step 16: load-balance flow-label both. Pseudowire Control Word. Pseudowire identifier (PW ID) FEC TLV:€Identifies the Pseudowire that the label is bound to Label TLV€ <- LDP uses to advertised the MPLS label. The control word attribute can be set using commands or a PW template. 1. 3. Configuring; Configuring - The control word as defined in Section 4. Pseudowire Control Word Negotiation Mechanism Analysis and Update draft-jin-pwe3-cbit-negotiation-04 1 PWE3 IETF80 Lizhong Jin Raymond Key Thomas Nadeau Simon Delord - Control word bit (C) The bit (C) is used to flag the presence of a control word as follows: C = 1 Control word present on this PW. This new type of S-PE can be deployed in the network one hop away Jan 24, 2023 · This document describes the preferred design of a Pseudowire Emulation Edge-to-Edge (PWE3) Control Word to be used over an MPLS packet switched network, and the Pseudowire Associated Channel Header. A control word is an optional 4-byte field located between the MPLS label stack and the Layer 2 payload in the pseudowire packet. 1 VC ID: 1234 Output interface: Tu64336, imposed label stack {16 21} Preferred path: not configured Default path: active Jan 21, 2020 · This document describes Virtual Circuit Connectivity Verification (VCCV), which provides a control channel that is associated with a pseudowire (PW), as well as the corresponding operations and management functions (such as connectivity verification) to be used over that control channel. Jin, Ed. net, sboutros@cisco. VCCV applies to all supported access circuit and transport types currently defined for PWs. The IETF Pseudowire Emulation Edge-to-Edge (PWE3) working group has defined many encapsulations of various layer 1 and layer 2 service- specific PDUs and circuit data. This document Virtual private wire service (VPWS) Layer 2 VPNs employ Layer 2 services over MPLS to build a topology of point-to-point connections that connect end customer sites in a VPN. The This document describes the preferred design of a Pseudowire Emulation Edge-to-Edge (PWE3) Control Word to be used over an MPLS packet switched network, and the Pseudowire Associated Channel Header. Control words are used to distinguish a PW payload (Ethernet) from an IP payload (identified by the first nibble past the bottom MPLS label, either 4 or 6) carried over an MPLS network. Split horizon SAP groups and split horizon spoke SDP groups. 2, encounters a problem when a PE changes the preference for the use of the control word from NOT PREFERRED to PREFERRED. The PW ID FEC TLV contains: 1. While Type 2 (RA Label) is indicated as being "the preferred control word, then the pseudowire control word should be used. Load-balance IP over Ethernet pseudowire. If either endpoint prefers not to use the control word or does not support the control word, this procedure will cause it not to be used. 90. , R. They are the basic building blocks that can provide a point-to-point service as well as a multipoint service such as VPLS, which is practically a mesh of PWs used to create the bridge domain across which the packets flow. If either segment does not negotiate the control word, the control word is disabled for both segments. AToM Graceful Restart is negotiated independently on each pseudowire segment. The negotiation result for the control word is still not used, even though the use of control-word configuration on both PE1 and PE2 are PREFERRED. mpls control-word . If one endpoint prefers to use the control word but the other does not, the one that prefers not to use it has no extra protocol to execute; it just waits for a Label Mapping message that has C=0. Presence of zero-control-word in the payload indicates an Ethernet frame. This in turn may lead to the selection of the wrong equal-cost-multi-path (ECMP) path for the packet, leading in turn to the misordering Jul 11, 2017 · When the mpls control-word command is used in static pseudowire configurations, the command must be configured the same way on both ends of the connection to work correctly. Layer 2 services (such as Frame Relay, Asynchronous Transfer Mode, and Ethernet) can be emulated over an MPLS backbone by encapsulating the Layer 2 Protocol Data Units (PDUs) and then transmitting them over pseudowires (PWs). Nov 5, 2022 · The control word is optional for Ethernet, PPP, HDLC, and cell relay transport types. Boutros Status: Standards Track Stream: IETF Date: September 2012 Mailbox: lizhong. This document Dec 23, 2011 · Do not configure IP or Ethernet interworking on a router where L2VPN Pseudowire Switching is enabled. The conditions under which the control word is or is not used are specified below. cn, raymond. The design of these fields is chosen so that an MPLS Label Switching Router performing MPLS payload inspection will not confuse a PWE3 payload with Dec 15, 2023 · MPLSおよびIP上のレイヤ2(L2)トランスポートは、イーサネット間、PPP間、 High-Level Data Link Control(HDLC)など、類似の接続回線に対してすでに存在しています Update of the Pseudowire Control-Word Negotiation Mechanism. – It is easier to ensure control no ECMP behavior over a Link or a small-sized network – It is expected that T-PE1 and S-PE1 are one-hop away at the MPLS layer • This new S-PE can be added to the network with minimum or no service disruptio n – PW redundancy can be used to move the traffic from the original SS-PW to the new MS- Aug 14, 2024 · Pseudowire Scale Support; Structure-Agnostic TDM over Packet; How to Configure Pseudowire; Overview of CEM Pseudowire. Edited by: Kumar Sridhar. For MPLS pseudowires that use a connection verification (CV) type that does not include IP/UDP headers, you must set the CC type to CC type 1: pseudowire control word. Modified 7 years, 5 months ago. com. Ask Question Asked 7 years, 5 months ago. 168. Step 7: exit Example: Router(config-if-xconn)# exit Set control-word to request that other routers insert a control word between the label stack and the MPLS payload. [STANDARDS-TRACK] The control-word negotiation mechanism specified in RFC 4447 has a problem when a PE (Provider Edge) changes the preference for the use of the control word The pseudowire (PW) encapsulation of Ethernet, as defined in RFC4448, specifies that the use of the control word (CW) is optional. Control word . 0. E , and there is no meaning if I carry B ,F ,Discard eligible flags in martini encapsulation towards the other end P. However, there are several encapsulations for which the Control Word is optional, and this optionality has been seen in practice to possibly Pseudowire Control Word. But in (2) I just wonder why the need of Martini control word is there. Pseudowire signaling details The pseudowire is set up using the following NLRI fields: This document describes Connectivity Verification (CV) Types using Bidirectional Forwarding Detection (BFD) with Virtual Circuit Connectivity Verification (VCCV). Step 7 Control Word (CW) A four-octet header used in some encapsulations to carry per-packet information when the PSN is MPLS. RFC 4385 Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use over an MPLS PSN; RFC 4448 Encapsulation Methods for Transport of Ethernet over MPLS Networks; RFC 4447 Pseudowire Setup and Maintenance - Using the Label Distribution Protocol (LDP) RFC 4553 Structure-Agnostic Time Division Multiplexing (TDM) over Packet (SAToP) The following sections describe how to configure interfaces for Layer 2 circuits: This document describes how to connect pseudowires (PWs) between different Packet Switched Network (PSN) domains or between two or more distinct PW control plane domains, where a control plane domain uses a common control plane protocol or instance of that protocol for a given PW. [STANDARDS-TRACK] The control-word negotiation mechanism specified in RFC 4447 has a problem when a PE (Provider Edge) changes the preference for the use of the control word from NOT PREFERRED to PREFERRED. • mpls control-word • mpls label • show mpls l2transport vc • xconnect. The presence of the control word is indicated by the C bit of the FEC element used in LDP signaling. Feb 1, 2006 · This document describes the preferred design of a Pseudowire Emulation Edge-to-Edge (PWE3) Control Word to be used over an MPLS packet switched network, and the Pseudowire Associated Channel Header. 6, "The Control Word", is, if necessary, prepended to the resulting frame. - The proper pseudowire demultiplexer (PW Label) is prepended to the resulting packet. Jul 24, 2006 · Thank Harold for your reply. However, in the case where a PE changes its preference from NOT PREFERRED to PREFERRED and both ends of the PW (pseudowire) PE have the use of control word set as PREFERRED, an incorrect negotiated result of the control word as "not used" occurs. com, tnadeau@juniper. Because , if one end of the attached circuit is FR , the L2 header will be chopped off at the P. In the absence of the CW an Ethernet pseudowire packet can be misidentified as an IP packet by a label switching router (LSR). To disable the control word, use the no form of this command. Object grouping and state monitoring. org, simon. The pseudowire tunnel acts as an unshared link or circuit of the emulated service. Control Word Bit (C-Bit)—The C-bit indicates whether the advertising PE expects the control word to be present for pseudowire packets. Early Ethernet PW implementations have been deployed that do not include a control word or the ability to process one if present. Configuring; Configuring Feb 1, 2006 · This document describes the preferred design of a Pseudowire Emulation Edge-to-Edge (PWE3) Control Word to be used over an MPLS packet switched network, and the Pseudowire Associated Channel Header. To enable the Multiprotocol Label Switching (MPLS) control word in an Any Transport over MPLS (AToM) static pseudowire connection, use the mpls control-word command in xconnect configuration mode. Nov 5, 2022 · AToM control word processing is not performed at the L2VPN Pseudowire Switching aggregation point. 2012-09 Proposed Standard RFC Obsoleted by rfc8077: Stewart Bryant: 35 pages Pseudowire control word. This document updates RFC 4447 and RFC 6073 by adding the Label Request message to resolve this control-word negotiation issue for single-segment and multi-segment pseudowires. , and G. Example: Device(config-pw-class)# load-balance flow-label both 5. 18. It is also possible to use pseudowires to provide low-rate Time-Division Multiplexed and Synchronous Optical NETworking circuit emulation over an MPLS-enabled network Feb 13, 2021 · Below are the three real live interfaces. Maximum Transmission Unit (MTU) The control word command provides the option to add a control word as part of the packet encapsulation for PW types for which the control word is optional. 1AX-2008 (originally specified as IEEE 802. 202 12 reply mode control-channel”. LDP Pseudowire LDP pseudowire provides support for emulating Ethernet connections over a Multiprotocol Label Switching (MPLS) network, and controlled using the extension of the MPLS Label Distribution Protocol (LDP) specified in RFC4447. This document updates RFC 4447 and RFC 6073 by adding the Label Request message to resolve this control-word negotiation issue for single-segment and multi This document updates RFC 4447 and RFC 6073 by adding the Label Request message to resolve this control-word negotiation issue for single-se segment and multi-segment pseudowires. Network Working Group Lizhong Jin (ed. RFC 4385 PW3 Control Word for Use over an MPLS PSN February 2006 This document specifies how the PW control word is used to distinguish a PW payload from an IP payload carried over an MPLS PSN. Mar 19, 2014 · vccv {control-word | router-alert | ttl} Example:Router(config-pw-class)# vccv control-word Sets the MPLS pseudowire control channel (CC) type. This is because for ATM signals Jun 2, 2014 · For other attachment circuits, the control word is included by default. VPLS access redundancy. delord@gmail. •At that time no Ethernet MAC address had been issued by the IEEE Registration Authority Committee (RAC) that started with 0x4 or 0x6, May 21, 2024 · Hi dear community, I have a good one for you regarding the setup of a vpls (ldp signaled) between a Cisco ISR1100X and a Juniper SRX300. Nadeau, S. The control-word negotiation mechanism specified in RFC 4447 has a problem when a PE (Provider Edge) changes the preference for the use of the control word from NOT PREFERRED to PREFERRED. C-bit: If set to 1 means that the control word is present. The PW control word (CW) is a 32-bit field that is inserted between the VC label and the Layer 2 frame. Jan 2, 2021 · P2#show l2vpn atom vc vcid 1234 detail pseudowire100001 is up, VC status is up PW type: Eth VLAN Create time: 00:18:39, last status change time: 00:18:22 Last label FSM state change time: 00:18:34 Destination address: 2. MAC flush message processing. The T-LDP control word signaling behavior is the same as that for the This example shows how to configure a dynamic multisegment pseudowire (MS-PW), where the stitching provider edge (S-PE) devices are automatically and dynamically discovered by BGP, and pseudowires are signaled by LDP using FEC 129. 1. Instead, configure interworking on the routers at the edge PEs of the network. 3ad-2000) Link Aggregation Group (LAG) that has been used in an MPLS network. [STANDARDS-TRACK] As a result of the Control Word being Mandatory, all implementations of the PWE3 encapsulations SHALL follow Section 6. ), Huawei Updates: 4447 (if approved) Simon Delord, Alcatel-Lucent Category: Standards Track Thomas Nadeau, CA Technologies Expires: April 19, 2012 Vishwas Manral, Hewlett-Packard Sami Boutros, Cisco Reshad Rahman, Cisco October 19, 2011 Pseudowire Control Word Sep 6, 2023 · If so far all is well, then you can try to ping the PW part internally by using the IOS command “ping mpls pseudowire 202. Both nodes are in Vlan 18 and has an IP **bleep** of 192. Inclusion of the control word can be explicitly disabled using the no mpls control-word command. The control word has these five functions: Pad small packets; Carry control bits of the layer 2 header of the transported protocol; Preserve the sequencing of the transported frames ; Facilitate the correct load balancing of AToM packet in the MPLS backbone network; Facilitate fragmentation and reassembly Jul 11, 2017 · To enable the MPLS control word in a static pseudowire connection, use the mpls control-word command in xconnect configuration mode. key@ieee. 1/24 & 192. ACL next-hop for VPLS The Layer 2 extended community proposed in RFC 4761 is used to signal pseudowire characteristics; for example, VPLS status, control word, and sequencing. Step 7 Aug 5, 2019 · Specifies the peer IP address and virtual circuit (VC) ID value of a Layer 2 VPN (L2VPN) pseudowire. When the control word is enabled, all VPLS packets are encapsulated along with the control word. Bryant & Pate Standards Track [Page 4] RFC 3985 PWE3 Architecture March 2005 Customer Edge (CE) A device where one end of a service originates and/or terminates. 168 A new Request for Comments is now available in online RFC libraries. •A pseudowire is a tunnelling mechanism. cgi uzh dieqif lbqrv iwyua dsfzvc awngm jdndnx xgcw zgwnnot sevyxz rlkn cgeq nzs ovhccq