Ip Interworking Vll Datapath; Figure 21: Ip Interworking Vll Datapath - Alcatel-Lucent 7750 SR OS Service Manual

IP Interworking VLL (Ipipe) Services

IP Interworking VLL Datapath

CE 1 [64.47.30.1/32]
FR SAP
1/1/1:100
CE 3 [64.47.31.1/32]
In order to be able to forward IP packets between CE 1 and CE 2 in
manually configured with both CE 1 and CE 2 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. PE
2 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 CE 1 IP address. PE 2
should silently discard any ARP request message received on the Ethernet SAP for an address
other than that of CE 1. Likewise, PE 2 should silently discard any ARP request message with the
source IP address other than that of CE 2. In all cases, PE 2 keeps track of the association of IP to
MAC addresses for ARP requests it receives over the Ethernet SAP.
In order to forward unicast frames destined to CE 2, PE 2 needs to know CE 2 MAC address.
When the Ipipe SAP is first configured and administratively enabled, PE2 sends an ARP request
message for CE 2 MAC address over the Ethernet SAP. Until an ARP reply is received from CE2,
providing CE2's MAC address, unicast IP packets destined for CE2 will be discarded at PE2. IP
broadcast and IP multicast packets are sent on the Ethernet SAP using the broadcast or direct-
mapped multicast MAC address.
In order to forward unicast frames destined to CE 1, PE 2 validates the MAC destination address
of the received Ethernet frame. It should match that of the Ethernet SAP. It then removes the
Ethernet header and encapsulates the IP packet directly into a PW without a control word. PE 1
removes the PW encapsulation and forwards the IP packet over the Frame Relay SAP using RFC
2427, Multiprotocol Interconnect over Frame Relay, routed PDU encapsulation.
In order to forward unicast packets destined to CE1, PE2 validates the MAC destination address of
the received Ethernet frame. If the IP packet is unicast, the MAC destination must match that of
the Ethernet SAP. If the IP packet is multicast or broadcast, the MAC destination address must be
an appropriate multicast or broadcast MAC address. The other procedures are similar to the case of
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7750 SR
PE 1
ATM SAP Ethernet VLAN
2/1/1:0/100 SAP 3/1/1:1001
CE 4 [64.47.31.2/32]
Figure 8: IP Interworking VLL Datapath
7750 SR
IP PW
IP/MPLS
PE 2
7750 SR OS Services Guide
CE 2 [64.47.30.2/32]
Ethernet/VLAN
SAP 1/1/1:1000
IPIPE_001
Figure 21, the PE 2 is