12-02-2007 01:55 PM - edited 03-05-2019 07:46 PM
I am using 6 x 3750G stacks in a distribution layer.
I connect 24 other 2 x 3750G switch stacks to the distro with 4GB Etherchannel trunks.
For almost every 4GB bundle I cannot get the 4th link to maintain 1G speed and it goes down to 100meg causing a compatibility problem with the etherchanel.
I am guessing that this is a Asic bug or hardware limitation?
Can anyone advise? SHould I contact Cisco TAC?
12-02-2007 02:36 PM
Could be hardware since you have a pattern of every 4th link. Contact cisco TAC if this is affecting business performance.
12-02-2007 06:15 PM
Can you post your config of your channel and channel interfaces?? you can use this page to check your cross stack channel config. You should be able to do 8 ports in a channel.
12-03-2007 01:26 PM
Group Port-channel Protocol Ports
------+-------------+-----------+-----------------------------------------------
1 Po1(SU) - Gi1/0/1(P) Gi1/0/2(P) Gi4/0/1(P)
Gi4/0/2(P)
2 Po2(SU) - Gi1/0/3(P) Gi1/0/4(P) Gi4/0/3(D)
Gi4/0/4(P)
3 Po3(SU) - Gi1/0/5(P) Gi1/0/6(P) Gi4/0/5(P)
Gi4/0/6(P)
4 Po4(SU) - Gi1/0/7(P) Gi1/0/8(P) Gi4/0/7(P)
Gi4/0/8(P)
5 Po5(SU) - Gi2/0/1(P) Gi2/0/2(P) Gi5/0/1(D)
Gi5/0/2(P)
6 Po6(SU) - Gi2/0/3(D) Gi2/0/4(P) Gi5/0/3(P)
Gi5/0/4(P)
7 Po7(SU) - Gi2/0/5(P) Gi2/0/6(P) Gi5/0/5(P)
Gi5/0/6(P)
8 Po8(SU) - Gi2/0/7(D) Gi2/0/8(D) Gi5/0/7(P)
Gi5/0/8(D)
9 Po9(SU) - Gi3/0/1(P) Gi3/0/2(P) Gi6/0/1(P)
Gi6/0/2(P)
10 Po10(SU) LACP Gi3/0/3(P) Gi3/0/4(P) Gi6/0/4(P)
11 Po11(SU) - Gi3/0/5(D) Gi3/0/6(P) Gi6/0/5(P)
Gi6/0/6(P)
12 Po12(SU) - Gi3/0/7(P) Gi3/0/8(P) Gi6/0/7(P)
Gi6/0/8(P)
13 Po13(SU) - Gi1/0/9(P) Gi1/0/10(P) Gi4/0/9(P)
Gi4/0/10(P)
14 Po14(SU) - Gi1/0/11(P) Gi1/0/12(P) Gi4/0/11(D)
Gi4/0/12(P)
15 Po15(SU) - Gi2/0/9(P) Gi2/0/10(P) Gi5/0/9(P)
Gi5/0/10(P)
16 Po16(SU) - Gi2/0/11(P) Gi2/0/12(P) Gi5/0/11(P)
Gi5/0/12(P)
17 Po17(SU) - Gi3/0/9(P) Gi3/0/10(P) Gi6/0/9(P)
Gi6/0/10(P)
18 Po18(SU) - Gi3/0/11(P) Gi3/0/12(D) Gi6/0/11(P)
Gi6/0/12(P)
19 Po19(SU) - Gi2/0/13(D) Gi2/0/14(D) Gi5/0/13(P)
Gi5/0/14(P)
20 Po20(SU) - Gi2/0/15(P) Gi2/0/16(P) Gi5/0/15(D)
Gi5/0/16(D)
21 Po21(SU) - Gi1/0/13(P) Gi1/0/14(P) Gi4/0/13(P)
Gi4/0/14(P)
22 Po22(SU) - Gi1/0/15(P) Gi1/0/16(P) Gi4/0/15(P)
Gi4/0/16(P)
23 Po23(SD) - Gi3/0/13(D) Gi3/0/14(D) Gi6/0/13(D)
Gi6/0/14(D)
24 Po24(SD) - Gi3/0/15(D) Gi3/0/16(D) Gi6/0/15(D)
Gi6/0/16(D)
As you see I had to shutdown almost all of the 4th ports as they dont allow to stay 1GB and go to 100M.
My EC configs look like this.
interface GigabitEthernet5/0/1
switchport trunk encapsulation dot1q
switchport mode trunk
switchport nonegotiate
shutdown
channel-group 5 mode on
end
interface GigabitEthernet5/0/2
switchport trunk encapsulation dot1q
switchport mode trunk
switchport nonegotiate
channel-group 5 mode on
end
if I unshut the Downed ports, they go into suspended mode. The connecting switches have exact configs.
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