Hi,
I have attached a document describing what hsma is all about in more detail, including sample configurations.
In very simple words. It is a mechanism, a little bit like hsrp, to allow to cip's to backup each other. You configure a virtual adapter which is always only active on one of the two cip's and they monitor each other. If one cip goes down, the other one takes over and activates the virtual adapter.
When the two cip routers were connected to a tokenring infrastructure than the redundancy whas achived by using the same mac address on the cip's reachable over to different source bridged path using different rif's.
If you connect the two cip routers via a ethernet than there is no rif field in your packets anymore, you can not do source bridging. Additional the cam table of a ethernet switch can not deal with two times the same mac address on different ports in the same vlan.
Hsma allows for a similar level of redundancy if your cip routers are connected via a ethernet backbone.
thanks...
Matthias
