3Com 4007, Implementation Manual, Page: 412 / 684

412 C
HAPTER
17: V
IRTUAL
R
OUTER
R
EDUNDANCY
P
ROTOCOL
(VRRP)
Problem
The backplane port router of BA2 does not have the ability to address the
44.4.53 and 55.5.53 subnetworks on the front panel port router of BA1.
With RIP-2 or OSPF: The routing protocol advertises a path to
subnetworks 44.4.53 & 55.5.53 through the 22.2.52.17 address, (the
backplane port router of the BA1 module). When the front panel router
port on BA2 goes down:
■
The backplane port router of BA2 updates its routing table from the
advertisement of BA1 because the BA2 backplane port router no
longer has subnetworks 44.4.53 & 55.5.53 as locally attached
networks.
■
The backplane port router of BA2
acquires
addressability to
subnetworks 44.4.53 & 55.5.53 by means of the backplane port
router of BA1.
The routing table for the backplane port router of BA2 shows 22.2.52.17
as the next hop for the subnetworks 44.4.53 & 55.5.53.
The backplane port of BA1 is still the Backup VRRP router and the
backplane port of BA2 is still the Master VRRP router for locally-attached
end stations (VRRP VID 52). Traffic flow between end station 1 and end
station 2 progresses in the following manner:
VRRP with a Single
Virtual Router
The topology shown in this section is a variation of the VRRP Topology
seen in Figure 48. This topology has a single one-armed router handling
routing between subnetworks for both interchassis and intrachassis
traffic in a single, flat network.
Traffic from Goes to
22.2.52.1 (end station 1) 22.2.52.16 (BA2/backplane port default
gateway for end station 1)
22.2.52.16 (BA2/backplane port) 22.2.52.17 (BA1/backplane port, next hop to
55.5.53.4)
22.2.52.17 (BA1/backplane port) 55.5.53.17 (BA1/front panel port)
55.5.53.17 (BA1/front panel port) 55.5.53.5 (end station 2)