Re: STP - Where to Start

tomsund11 · ‎03-06-2011

Hi Guys,

I have a network consisting of a L3 3560, 2960's and HP 2650's in a loop.

When connecting a new machine up it can take quite a while to get an IP address, I understand this is due to the switch port 'listening' for 30 or so seconds?

Is it possible to reduce this time?

I appreciate I haven’t given much detail here (I'm not a networking Guru ) but can always run some show commands etc. when pointed in the right direction!

Thanks for reading.

Tom

cadet alain · ‎03-06-2011

Hi,

to reduce this time you can enable portfast on access ports , on cisco switches the command is spanning-tree portfast under interface or you can use the global config command: spanning-tree portfast default which will enable automatically this feature on access ports.

No need for anything special on hp switch if rapid spanning-tree is configured.

Regards.

Alain.

Don't forget to rate helpful posts.

tomsund11 · ‎03-06-2011

Ahh interesting, we use multiple spanning tree... MSTP.

Not sure where to go from here? Is there an option in MSTP or should/can we transition to rapid STP?

Tom

Peter Paluch · ‎03-06-2011

Hello,

MSTP runs RSTP internally, so that is fine.

However, declaring the edge ports explicitly using the spanning-tree portfast or using the global configuration mode command spanning-tree portfast default is extremely necessary in RSTP and MSTP - even more than in STP.

So please, if possible, use the command spanning-tree portfast default in the global configuration mode on your Catalyst switches. The HP switches should already have the ports configured as "auto-edge" which should be sufficient.

Best regards,

Peter

tomsund11 · ‎03-07-2011

Hi Peter,

Pretty much all of my edge ports are on the HP switches so (possibly the wrong forum) but I can't see any 'auto-edge' settings either in the GUI or CLI, the software on these switches is dated 2005 (8.60), is the auto-edge stuff new or am I looking in the wrong place?

Thanks,

Tom

Peter Paluch · ‎03-07-2011

Hello Tom,

To be frank, I am not sure. I do work with HP ProCurve devices but not nearly as often as with Cisco. In any case, the command I see is spanning-tree auto-edge-port in the global configuration mode. The setting can be then verified using the command show spanning-tree detail, as follows:

Switch# show spanning-tree 1 detail

Status and Counters - CST Port(s) Detailed Information

Port                      : 1
Status                    : Up
BPDU Protection           : No
BPDU Filtering            : No
PVST Protection           : No
PVST Filtering            : No
Errant BPDU Count         : 0
Root Guard                : No
TCN Guard                 : No
MST Region Boundary       : Yes
External Path Cost        : 200000
External Root Path Cost   : 0
Administrative Hello Time : Global
Operational Hello Time    : 2
AdminEdgePort             : No
Auto Edge Port            : Yes
OperEdgePort              : Yes
AdminPointToPointMAC      : True
OperPointToPointMAC       : Yes
Aged BPDUs Count          : 0
Loop-back BPDUs Count     : 0
TC ACK Flag Transmitted   : 0
TC ACK Flag Received      : 0

MST        MST        CFG        CFG        TCN        TCN
BPDUs Tx   BPDUs Rx   BPDUs Tx   BPDUs Rx   BPDUs Tx   BPDUs Rx
---------- ---------- ---------- ---------- ---------- ----------
525114     0          0          0          0          0

I guess that having a look into the respective Configuration Guide for your switch would be helpful, along with possibly upgrading the firmware.

Best regards,

Peter