Ip Unicast Routing; Router Interfaces; Populating The Routing Table; Routing Between Vlans - Extreme Networks Summit 300-48 Software User's Manual

IP Unicast Routing

Router Interfaces

The routing software and hardware routes IP traffic between router interfaces. A router interface is
simply a 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 17, a Summit 300-48 switch is depicted with two VLANs defined; Finance and Personnel. Ports
2 and 4 are assigned to Finance; ports 3 and 5 are assigned to Personnel. Finance belongs to the IP
network 192.207.35.0; the router interface for Finance is assigned the IP address 192.206.35.1. 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 17: Routing between VLANs
192.207.35.1 192.207.36.1
192.207.35.0 192.207.36.0
Finance Personnel
2 3 4 5
192.207.35.11
192.207.35.13
192.207.36.14
192.207.36.12
EW_090

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 ICMP redirects exchanged with other routers
• Statically, by way of routes entered by the administrator
— Default routes, configured by the administrator
194 Summit 300-48 Switch Software User Guide