On 26/01/10 16:34, Steven Pfister wrote:
I'm trying to troubleshoot connectivity problems between a virtual
server at a central site and PCs in the same vlan at a remote site.
At the central site is several VMWare servers connected to a 3560
switch. The PCs at the remote site need to reach this virtual server,
and while most do, some have trouble seeing it.
A common thread seems to be whether the 3560 has been able to learn
the MAC address of the PC. If it hasn't, we can put in a static
address and everything is OK.
I'm wondering... is there a limit to the number of dynamic MAC
Yes. Obviously all devices have a hard limit based on RAM or hardware
CAM size. Your actual limit may be lower than the theoretical max - see
below.
addresses that a switch like the 3560 can learn? If so, can that
limit be changed, and is the situation the same for static
Maybe
addresses?
Maybe.
I've not used the 3560, but on 3550 and 3750 there is a concept of a
thing called an "SDM" template, which partitions the hardware resources
into certain sized buckets depending on the use of the switch.
e.g. one of ours says:
rt1#sh sdm prefer
The current template is "aggregate IPv4 and IPv6 default" template.
The selected template optimizes the resources in
the switch to support this level of features for
8 routed interfaces and 1024 VLANs.
number of unicast mac addresses: 2K
number of IPv4 IGMP groups + multicast routes: 1K
I'm not sure how static MAC entries are handled, but I'm willing to bet
they'll take precedence over dynamic ones, so adding a static might
"push" someone else out.
Other templates have numbers like:
rt1#sh sdm prefer access
"aggregator access IPv4" template:
The selected template optimizes the resources in
the switch to support this level of features for
8 routed interfaces and 1024 VLANs.
number of unicast mac addresses: 6K
...or:
rt1#sh sdm prefer vlan
"aggregate vlan" template:
The selected template optimizes the resources in
the switch to support this level of features for
8 routed interfaces and 1024 VLANs.
number of unicast mac addresses: 12K
What does:
sh mac address-table count
...say?
If your device does need the SDM template changing, it will need a
reboot to take effect I'm afraid.
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