Switch to 3825... stp?
Here's one for ya, techies...
I'm installing a 3825 at our office, as we move from ATM to MPLS. The router will connect to a 3750 stack en route to our core.
The question of stp traffic came up, between the Cat and the 3825.
So, by default, will bpdu's be shared between these two devices?
Does the 3825 generate bpdu's?
If not (which I suspect), what would be the implications of turning on portfast on the switch port directly connected to the router? Would this essentially kill stp traffic on the link?
Thanks,
Mike
I'm installing a 3825 at our office, as we move from ATM to MPLS. The router will connect to a 3750 stack en route to our core.
The question of stp traffic came up, between the Cat and the 3825.
So, by default, will bpdu's be shared between these two devices?
Does the 3825 generate bpdu's?
If not (which I suspect), what would be the implications of turning on portfast on the switch port directly connected to the router? Would this essentially kill stp traffic on the link?
Thanks,
Mike
There are only 10 kinds of people... those who understand binary, and those that don't.
CCIE Studies: Written passed: Jan 21/12 Lab Prep: Hours reading: 385. Hours labbing: 110
Taking a time-out to add the CCVP. Capitalizing on a current IPT pilot project.
CCIE Studies: Written passed: Jan 21/12 Lab Prep: Hours reading: 385. Hours labbing: 110
Taking a time-out to add the CCVP. Capitalizing on a current IPT pilot project.
Comments
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dtlokee
Member Posts: 2,378 ■■■■□□□□□□
What type of module are you connecting the switch to in the rotuer? As long as it's not a switching module in L2 mode there is no reason why you need STP on the link. Using portfast will bypass the STP forwarding delay and is basically the same as disabling STP on the interface.The only easy day was yesterday! -
mikearama
Member Posts: 749
The 3825 comes with two gig ports built in... one to our core (through the 3750), the other to Bell's CE 3800.
I think the same way you do, dt. However, I noted one thing on the 3825 that made me hesitate... it's running cef by default. I've found nothing that suggests cef and bpdu's are synonymous... just hoping you can confirm that.There are only 10 kinds of people... those who understand binary, and those that don't.
CCIE Studies: Written passed: Jan 21/12 Lab Prep: Hours reading: 385. Hours labbing: 110
Taking a time-out to add the CCVP. Capitalizing on a current IPT pilot project. -
networker050184
Mod Posts: 11,962 Mod
If this is a routed port you don't have to worry about STP.
CEF and STP are not synonomous. CEF is enabled by deafult on all fairly recent routers.An expert is a man who has made all the mistakes which can be made. -
MACattack
Member Posts: 121
Man , the only way to stop sending BPDU if you apply BPDU filters on L2 port interface, as you mentioned it is connected to the router and if you enable bpdu portfast, then it should be great as it will transition to forward mode.
So to make sure apply BPDU filter and use network sniffer to see if the switch is sending BPDU even though you connected to the router as it is a waste of BW in the link..