Trunking Not Working Cisco 2960 connecting to Juniper 2300

[blakecrossley]

Hi there

 I am trying to trunk port 1/0/24 on a Cisco 2960 to a Juniper 2300. I am getting the following error.
SSWC-MEDIABOOTH-1#
.May 23 21:18:30.358 MDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/24, changed state to down
SSWC-MEDIABOOTH-1#
.May 23 21:18:31.364 MDT: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/24, changed state to down
SSWC-MEDIABOOTH-1#
.May 23 21:18:38.894 MDT: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/24, changed state to up
.May 23 21:18:39.911 MDT: %SPANTREE-2-PVSTSIM_FAIL: Blocking designated port Gi1/0/24: Inconsitent superior PVST BPDU received on VLAN 27, claiming root 8200:0008.e3ff.fd90
SSWC-MEDIABOOTH-1#
.May 23 21:18:39.958 MDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan27, changed state to up
.May 23 21:18:40.907 MDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/24, changed state to up
SSWC-MEDIABOOTH-1#
.May 23 21:18:43.974 MDT: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking GigabitEthernet1/0/24 on MST0. Inconsistent local vlan.
SSWC-MEDIABOOTH-1#
.May 23 21:18:43.985 MDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan27, changed state to down
SSWC-MEDIABOOTH-1#
.May 23 21:18:45.961 MDT: %SYS-6-LOGGINGHOST_STARTSTOP: Logging to host 172.18.1.63 port 514 started - reconnection
SSWC-MEDIABOOTH-1#
.May 23 21:18:50.968 MDT: %SYS-6-LOGGINGHOST_STARTSTOP: Logging to host 172.18.3.66 port 514 started - reconnection
SSWC-MEDIABOOTH-1#
.May 23 21:19:03.976 MDT: %SPANTREE-2-PVSTSIM_OK: PVST Simulation inconsistency cleared on port GigabitEthernet1/0/24.

[Mark Malone]

Hi
Looks like some form of STP issues between Juniper and Cisco
Ciscos probably running PVST , is juniper running MST STP ?

is it dual, linked or single linked between these switches

[Giuseppe Larosa]

Hello blakecrossley,

It looks like you are running MST on the Cisco device

>> May 23 21:18:43.974 MDT: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking GigabitEthernet1/0/24 on MST0

And that PVST is running on the Juniper side:

.May 23 21:18:39.911 MDT: %SPANTREE-2-PVSTSIM_FAIL: Blocking designated port Gi1/0/24: Inconsitent superior PVST BPDU received on VLAN 27, claiming root 8200:0008.e3ff.fd90

To fix this issue:

a) the best option is to configure the Juniper switch to take part to the same MST region

b) or you should increase the STP priority on the Juniper side to avoid the failure of the consistency check at MST / PVST border link.

Having all devices running MST is the best long term solution. Be sure that the Juniper will not be the root bridge.

Hope to help

Giuseppe