Appendix D. Setting Up Network Switches; General Networking Notes; Switch Commands; Vlan - IBM Cluster 1350 Installation And Service

Appendix D. Setting up network switches

Contents

General networking notes

When setting up switches in the 512 mode or any time there intentionally are
multiple connections between switches you must designate one of the core
switches as the spanning tree root. In the case of the 512 node configuration it
must be one of the 4006's.
When setting up VLANs on a 4006 running Catos make sure to set the vtp domain
name. This can be any name since we are not using vtp to maintain the VLANs.
3508/3524 switches only have 1 virtual Ethernet port. This can be assigned to any
VLAN on the switch. Which ever VLAN it is assigned to should be designated as
the Management VLAN for the switch.
4006 running IOS can have an IP connection for each VLAN. However the
management port on the SUP card can only be used for recovery situations. 1 port
in the Management VLAN can be dedicated to hook up the management network
to the 4006.
4006 running Catos has one port that can be used for an Ethernet connection. It is
sc0 and can be in any VLAN. For our purposes it should be assigned to the
Management VLAN. Again one port assigned to the Management VLAN needs to
be reserved to make the connection to the switch itself. It is the same story as
above for the management port on the SUP card.
Load balancing across Etherchannels is an important performance point. This is
something that would be unique to the jobs that the customer intends to run on
the cluster.
To split networks, creating a primary cluster VLAN and a Management VLAN in
the switches, requires an extra connection between the 3550 and the 3508.
RJ45 (copper) adapter GBICS must be connected to a gigabit port or it will not
link. Those GBICS will not negotiate speed.
The Linux kernel by default supports proxy arping. This can cause problems on a
shared media network. If you have more that one NIC in the same broadcast
domain the problem will happen. Proxy arping allows either interface in the
broadcast domain to respond to an arp request. This can cause IP traffic to be
handled by an interface other than the intended one. The only way to prevent this
is to create separate VLANs in the switches.

Switch commands

Switch commands for 3508/3550 running IOS
These commands will work with a 4006 running IOS as well. To set up VLANs
issue the following commands:
© Copyright IBM Corp. 2003
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