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SRW2048 - RSTP Costs

Hi,

I just found out that the SRW2048 uses wrong costs for port-channels.

g47   enabled   128.47    20000    FRW   Root    No       P2p (RSTP)    
ch1   enabled   128.53    20000    BLK   Altn    No       P2p (RSTP)

ch1 consists of two interfaces and should have 10.000 as cost.

ch1 is connected to a Cisco 3560-E and on this side everything works fine:


Port 104 (Port-channel7) of MST0 is designated forwarding
   Port path cost 10000, Port priority 128, Port Identifier 128.104.


Port-channel7 is up, line protocol is up (connected)
  Hardware is EtherChannel, address is X.Y.Z (bia X.Y.Z)
  MTU 1500 bytes, BW 2000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, link type is auto, media type is unknown
  input flow-control is off, output flow-control is unsupported
  Members in this channel: Gi0/13 Gi0/14

Why doesn't take the SRW2048 the interface speed of port-channels in account? This makes a redundant backup link with spanning-tree a nightmare because you have to set the costs manually.

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1 REPLY

Re: SRW2048 - RSTP Costs

Hi Jens,

Port costs is normally one way and the easiest may I manually select root port or alternate port in a RSTP environment.

i am a bit perplexed by the scenario you mentioned, but glad you have a solution.

This I guess was an observation on the older SRW2048 and not the refreshed 300 series product SRW2048-K9-NA ?

New product, just released product comparisons, URL follows;

http://www.cisco.com/en/US/products/ps10898/prod_models_comparison.html

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