Implementing IBM System Networking 10Gb Ethernet Switches

82 Implementing IBM System Networking 10Gb Ethernet Switches

Static trunks

When you add a portchannel (static trunk group) to a failover trigger, any ports in that trunk

become members of the trigger. You can add up to 64 static trunks to a failover trigger, using

manual monitoring.

Link Aggregation Control Protocol

LACP allows the switch to form dynamic trunks. You can use the admin key to add up to two

LACP trunks to a failover trigger by using automatic monitoring. When you add an admin key

to a trigger, any LACP trunk with that admin key becomes a member of the trigger.

Spanning Tree Protocol

If STP is enabled on the ports in a failover trigger, the switch monitors the port STP state

rather than the link state. A port failure results when STP is not in a Forwarding state (such as

Listening, Learning, Blocking, or No Link). The switch automatically disables the appropriate

control ports.

When the switch determines that ports in the trigger are in the STP Forwarding state, then it

automatically enables the appropriate control ports. The switch fails back to normal operation.

2.7.6 Virtual Router Redundancy Protocol

IBM System Networking switches support IPv4 high-availability network topologies through

an enhanced implementation of the Virtual Router Redundancy Protocol (VRRP).

Virtual Router Redundancy Protocol overview

In a high-availability network topology, no device can create a single point of failure for the

network or force a single point-of-failure to any other part of the network. This situation means

that your network remains in service despite the failure of any single device. To achieve this

goal usually requires redundancy for all vital network components.

VRRP enables redundant router configurations within a LAN, providing alternative router

paths for a host to eliminate single points of failure within a network. Each participating

VRRP-capable routing device is configured with the same virtual router IPv4 address and ID

number. One of the virtual routers is elected as the master, based on a number of priority

criteria, and assumes control of the shared virtual router IPv4 address. If the master fails, one

of the backup virtual routers takes control of the virtual router IPv4 address and actively

processes traffic addressed to it.

With VRRP, Virtual Interface Routers (VIR) allow two VRRP routers to share an IP interface

across the routers. VIRs provide a single Destination IPv4 (DIP) address for upstream routers

to reach various servers, and provide a virtual default gateway for the servers.

Virtual Router Redundancy Protocol components

Each physical router that runs VRRP is known as a VRRP router.

Virtual router

Two or more VRRP routers can be configured to form a virtual router (For more details, see

RFC 2338 at http://www.ietf.org/rfc/rfc2338.txt). Each VRRP router may participate in

one or more virtual routers. Each virtual router consists of a user-configured virtual router

identifier (VRID) and an IPv4 address.