Multihoming; Circuitless Ip - Avaya 8800 Configuration Manual

Routing fundamentals
If a spoofed packet is sent, the following actions occur:
• The client sends a packet to the server with a forged IP address of 192.32.46.10 through
port 7/2.
• Reverse path checking finds that the source IP address next-hop port is 7/1, which does
not match the packet incoming port of 7/2. In this case, the packet is discarded.
You can think about RPC as follows. If packets are sent from A to B through route X ingress
port Y , then the return packets from B to A should egress X through the same port Y . If returning
packets take a different path, they are dropped.

Multihoming

Using the multihoming feature, the Ethernet Routing Switch 8800/8600 can support clients or
servers that have multiple IP addresses associated with a single Media Access Control (MAC)
address. Multihomed hosts can be connected to port-based, policy-based, and IP subnet-
based VLANs.
The IP addresses associated with a single MAC address on a host must be in the same IP
subnet. Multihomed hosts with up to 16 IP addresses for each MAC address are supported.

Circuitless IP

Circuitless IP (CLIP) is a virtual (or loopback) interface that is not associated with a physical
port. You can use the CLIP interface to provide uninterrupted connectivity to your switch if a
path is available to reach the device.
A CLIP address, or a loopback address, is an IP address that is not tied to a specific interface.
Because the CLIP is not tied to a physical port or VLAN, the CLIP state is always active.
You can use a CLIP as the OSPF Router ID if required. If you use BGP with OSPF, the OSPF
Router ID becomes the BGP identifier automatically. Therefore, in this case, Avaya
recommends that you use the CLIP as the OSPF Router ID. By doing so, the OSPF Router ID
is always active regardless of the port state (up or down).
For example, as shown in the following figure, a physical point-to-point link exists between R1
and R2 along with the associated addresses (195.39.1.1/30 and 195.39.1.2/30). An Interior
Border Gateway Protocol (IBGP) session exists between two additional addresses,
195.39.128.1/30 (CLIP 1) and 195.39.281.2/30 (CLIP 2).
28 Configuration — OSPF and RIP June 2011