Ethernet Ports on PRP-2

netservices · ‎09-05-2008

We have installed redundant PRP-2 modules in a 12010 chassis and we were under the impression that the Ethernet ports (eth0, eth1 and eth2) could be used for routing purposes.

I have found documentation on the older PRP modules which states -

" The PRP Ethernet port does not provide external routing functions. Its primary roles are to act as a Telnet port into the router, and to boot or access Cisco IOS software images over a network to which the PRP Ethernet port is directly connected"

What I cannot find is any information on the capabilities of the Ethernet ports on the newer PRP-2 modules and what the difference is between the Eth2 port and the Eth1 and Eth0 ports (apaprt from being 10/100/1000 capable).

Any advice on this would be extremely useful.

Regards

Steven

Giuseppe Larosa · ‎09-05-2008

Hello Steven,

those ports are for management purposes they are not supposed to be used for routing user traffic.

the risk is that all packets going through them are processed by the PRP-2 main cpu that should deal with building CEF tables for all linecards. There are no ASIC chips to manage the ports.

see

http://www.cisco.com/en/US/docs/routers/12000/12012/maintenance/guide/11656prp.html#wp237135

tells about limitations of eth ports

I wouldn't suggest to use them for other then management.

Hope to help

Giuseppe

netservices · ‎09-05-2008

Hi Giuseppe,

Thanks for you information.

I had a fair idea that this was the case based on the observations I had made when I attempted to route traffic across one of these ports i.e. excessive CPU utilisation.

A Gig port for management does seem like overkill but I guess thats Cisco for you.

Cheers

Steven