10-04-2007 06:11 AM - edited 03-05-2019 06:52 PM
Folks,
I have a 3750 switch connected to a 6509 switch using MM fiber and doing layer 3. Lately i have experienced some serious problems with this link. occassionaly,it used to go down and I needed to shut and unshut either end of the link in order to bring the link up.This used to happen since the interfaces were showing up and up at both end and yet were not reachable. i enabled udld on both interfaces yesterday and now when it goes down, the inetrface is errdisable due to udld as shown here in the output.
core01#sh int gig4/1
GigabitEthernet4/1 is down, line protocol is down (err-disabled)
Hardware is C6k 1000Mb 802.3, address is 000f.3577.a44a (bia 000f.3577.a44a)
Internet address is 10.5.x.y/24
MTU 1500 bytes, BW 1000000 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, media type is SX
input flow-control is off, output flow-control is off
Clock mode is auto
ARP type: ARPA, ARP Timeout 04:00:00
Last input 11:34:20, output 11:34:17, output hang never
Last clearing of "show interface" counters 1d23h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
core01#sh int gig4/1 status
Port Name Status Vlan Duplex Speed Type
Gi4/1 err-disabled 1 full 1000 1000BaseSX
and
core01#sh logg
Oct 3 19:10:36.125: %OSPF-5-ADJCHG: Process 222, Nbr 10.254.254.6 on GigabitEth
ernet4/1 from INIT to DOWN, Neighbor Down: Interface down or detached
Oct 3 19:10:36.073: %UDLD-SP-4-UDLD_PORT_DISABLED: UDLD disabled interface Gi4/
1, unidirectional link detected
Oct 3 19:10:36.073: %PM-SP-4-ERR_DISABLE: udld error detected on Gi4/1, putting
Gi4/1 in err-disable state
core01#
Any idea what could be happening and how do I resolve this?
10-04-2007 06:16 AM
Hi,
I think you should check your fiber. It seems the UDLD proces detected a unidirectional link so it seems one of the fibers is failing
10-04-2007 06:22 AM
I would do a couple of things:
1. Test the fiber link with a good 1000BaseX tester
2. Configure the trunk links for ON ON
3. Try UDLD aggressive mode if not already done.
4. Change the GBICs/SFPs on both ends of the link and RMA the old ones to TAC if replacements work fine.
10-04-2007 06:31 AM
Thanks folks but since the interfaces are routed,how do I turn the trunk ON ON ?
10-04-2007 06:52 AM
If they are not trunks, then you can omit that recommendation.
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