IBM Nortel Networks L2/3, Manual

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64
Nortel Networks L2/3 Ethernet Switch Module for IBM
Eserver
BladeCenter
configuration of this capability is included in 7.5.3, “Base configuration common to all
examples” on page 68.
For more information about BASP NIC teaming, refer to the BACS online help and BCM570X
Broadcom NetXtreme Gigabit Ethernet Teaming white paper, which is available at:
http://www.broadcom.com/collateral/wp/570X-WP100-R.pdf
7.3.3 Introduction to VRRP
Virtual Router Redundancy Protocol (VRRP) is a Layer 3 protocol used to enable switches to
back each other up in a way which is transparent to client and server computers. VRRP
works by defining an address which is shared between the switches. One switch which is the
Master is the only one which will answer to the shared address. One or more other switches
in Backup state are configured to take over from the master in the event of a failure. An
instance of VRRP is configured for each VLAN where a shared address is to be used. This
implies that if there is one VLAN for the internal ports and an additional VLAN for the external
ports, then there can be two instances of VRRP, providing a shared address on the internal
VLAN and a different shared address on the external VLAN. An example configuration which
illustrates this is in 7.7, “Advanced Layer 2 topology sample configurations” on page 80.
VRRP Priority
Each switch in a group running VRRP has a configured priority. When VRRP first becomes
active, the switch with the highest priority will become the Master switch. The master switch
sends out periodic
hello packets announcing that it is still operational. The backup switch
with the highest configured priority will take over when the hello packets are no longer
received.
There are configuration options, called
tracking
options, which adjust the priority of a switch
dynamically based on the number of certain categories of resources (such as ports) which
are available. Use of these options can allow a backup switch to take over even if the current
master is still running but has lost some of the tracked resources.
Notes:
򐂰 The BASP driver can be configured to use standards-based Port Aggregation
(802.3-ad) teaming. This is useful on HS40 blades or HS20 blades with the SCSI
sidecar, both of which have two ports connecting them to each switch module. Only
ports connected to the same switch should be teamed in this way.
򐂰 The current production version of the GbESM software(1.0.1.6) does not support
trunking on internal ports. The next (1.1) software release will add this function.
򐂰 The Nortel L2/7 GbESM (but not the L2/3 GbESM) supports a capability called Server
Load Balancing (SLB). This is not similar to the Broadcom Smart Load Balancing; it
involved multiple servers running the same application.
򐂰 Some of the previous descriptions contain
as is
information based on a test in our
specific environment with BASP 7.12.01, the latest as this paper is written, and might
differ in different environments or future software releases.