Specifications

Configuring Routing Between VLANs

Information About Routing Between VLANs

The FSSRP feature improves upon SSRP such that LANE server and BUS switchover for LANE clients

is immediate. With SSRP, a LANE server would go down, and depending on the network load, it may

have taken considerable time for the LANE client to come back up joined to the correct LANE server

and BUS. In addition to going down with SSRP, the LANE client would do the following:

• Clear out its data direct VCs

• Clear out its LE ARP entries

• Cause substantial signalling activity and data loss

FSSRP was designed to alleviate these problems with the LANE client. With FSSRP, each LANE client

is simultaneously joined to up to four LANE servers and BUSs. The concept of the master LANE server

and BUS is maintained; the LANE client uses the master LANE server when it needs LANE server BUS

services. However, the difference between SSRP and FSSRP is that if and when the master LANE server

goes down, the LANE client is already connected to multiple backup LANE servers and BUSs. The

LANE client simply uses the next backup LANE server and BUS as the master LANE server and BUS.

VLAN Interoperability

Cisco IOS features bring added benefits to the VLAN technology. Enhancements to ISL, IEEE 802.10,

and ATM LANE implementations enable routing of all major protocols between VLANs. These

enhancements allow users to create more robust networks incorporating VLAN configurations by

providing communications capabilities between VLANs.

Inter-VLAN Communications

The Cisco IOS supports full routing of several protocols over ISL and ATM LANE VLANs. IP, Novell

IPX, and AppleTalk routing are supported over IEEE 802.10 VLANs. Standard routing attributes such

as network advertisements, secondaries, and help addresses are applicable, and VLAN routing is fast

switched. Table 39 shows protocols supported for each VLAN encapsulation format and corresponding

Cisco IOS software releases.

Table 39 Inter-VLAN Routing Protocol Support

Protocol ISL ATM LANE IEEE 802.10

IP Release 11.1 Release 10.3 Release 11.1

Novell IPX (default

encapsulation)

Release 11.1 Release 10.3 Release 11.1

Novell IPX (configurable

encapsulation)

Release 11.3 Release 10.3 Release 11.3

AppleTalk Phase II Release 11.3 Release 10.3 —

DECnet Release 11.3 Release 11.0 —

Banyan VINES Release 11.3 Release 11.2 —

XNS Release 11.3 Release 11.2 —

CLNS Release 12.1 — —

IS-IS Release 12.1 — —