Router Interfaces; Populating The Routing Table - Extreme Networks ExtremeWare XOS Guide Manual

IPv4 Unicast Routing

Router Interfaces

The routing software and hardware routes IP traffic between router interfaces. A router interface is
simply a virtual LAN (VLAN) that has an IP address assigned to it.
As you create VLANs with IP addresses belonging to different IP subnets, you can also choose to route
between the VLANs. Both the VLAN switching and IP routing function occur within the switch.
NOTE
Each IP address and mask assigned to a VLAN must represent a unique IP subnet. You cannot configure the same
IP address and subnet on different VLANs.
In Figure 60, a BlackDiamond switch is depicted with two VLANs defined; Finance and Personnel. All
ports on slots 1 and 3 are assigned to Finance; all ports on slots 2 and 4 are assigned to Personnel. Finance
belongs to the IP network 192.207.35.0; the router interface for Finance is assigned the IP address
192.207.35.1. Personnel belongs to the IP network 192.207.36.0; its router interface is assigned IP address
192.207.36.1. Traffic within each VLAN is switched using the Ethernet MAC addresses. Traffic between
the two VLANs is routed using the IP addresses.
Figure 60: Routing between VLANs
1
192.207.35.0
Finance
1
192.207.35.11
192.207.36.12

Populating the Routing Table

The switch maintains an IP routing table for both network routes and host routes. The table is
populated from the following sources:
Dynamically, by way of routing protocol packets or by Internet Control Message Protocol (ICMP)
●
redirects exchanged with other routers
496
2 3 4 A
192.207.35.1 192.207.36.1
2 3 4
192.207.35.13
192.207.36.14
B 5 6 7
192.207.36.0
Personnel
8
EX_070
ExtremeWare XOS 11.3 Concepts Guide