Ip Interworking Vll Datapath; Figure 28: Ip Pseudowires Between Sar Nodes - Alcatel-Lucent 7705 Service Manual

CE-2
A PPP interface makes use of RFC 1332, The PPP Internet Protocol Control Protocol
(IPCP), PPP IPCP encapsulation of an IPv4 packet. The PW uses the IP Layer 2 transport
pseudowire encapsulation type.

IP Interworking VLL Datapath

In order to be able to forward IP packets between CE 1 and CE 3 in
manually configured with both CE 1 and CE 3 IP addresses. These are host addresses and
are entered in the /32 format. PE 2 maintains an ARP cache context for each IP interworking
VLL and responds to ARP request messages received on the Ethernet SAP. PE 2 responds
with the Ethernet SAP configured MAC address as a proxy for any ARP request for the CE 1
IP address. PE 2 silently discards any ARP request messages received on the Ethernet SAP
for addresses other than CE 1. Likewise, PE 2 silently discards any ARP request messages
with source IP addresses other than CE 3. In all cases, PE 2 keeps track of the association of
IP to MAC addresses for ARP requests it receives over the Ethernet SAP. All entries are
subject to aging.
In order to forward unicast frames destined for CE 3, PE 2 needs to know the MAC address
of CE 3. If there is no entry in the ARP cache, PE 2 sends an ARP request message for the
CE 3 MAC address over the Ethernet SAP.
IP broadcast and IP multicast packets are sent on the Ethernet SAP using the broadcast or
direct-mapped multicast MAC address.
7705 SAR OS Services Guide

Figure 28: IP Pseudowires Between SAR Nodes

CE-1
PPP
7705 SAR
PE1
PPP
7705 SAR
Metro
PE2
Ethernet
IP/MPLS
MPLS LSP
VLL Services
CE-3
Ethernet
IP Pseudowires
20146
Figure 28, PE 2 is
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