Table 6: Gre Pseudowire Payload Packet Descriptions; Figure 6: Gre Pseudowire Payload Packet Over Ethernet - Alcatel-Lucent 7705 Service Manual

Service Entities
Payload Packet
The payload encapsulation format for pseudowires over GRE is shown in
described in
Page 52
Table 6.

Figure 6: GRE Pseudowire Payload Packet over Ethernet

Table 6: GRE Pseudowire Payload Packet Descriptions

Field
Eth
IP
GRE
PW header
CW (optional)
PW payload
Note:
1. The only exception to the Ethertype is if the packets are address resolution protocol (ARP) packets. For
information on ARP, refer to the 7705 SAR OS Router Configuration Guide.
PW Payload
4 CW (optional)
4 PW Header
4 GRE
20 IP
14 or 18 Eth
Description
The Layer 2 transport header
In Release 3.0, the only Layer 2 protocol supported is Ethernet
MTU size depends on the encapsulation type (14 bytes for null
encapsulation and 18 bytes for dot1q encapsulation)
Indicates the transport protocol
The Ethertype is always set to IP (0x800), and in case of a
mismatch, the unexpected or illegal Ethertype counters are
(1)
increased
Indicates the encapsulation protocol
The pseudowire header identifies a service within the GRE
tunnel
The pseudowire control word (CW) is a 32-bit (4-byte) field that
is inserted between the VC label and the Layer 2 frame
For more information on the control word, see
Control Word on page 190
The PW payload is the payload of the service being
encapsulated (Ethernet, ATM, or TDM)
7705 SAR OS Services Guide
Figure 6 and
19873
Pseudowire