3750G bug or hardware limitation?

Unanswered Question
Dec 2nd, 2007

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?

I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Loading.
cisconoobie Mon, 12/03/2007 - 13:26

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.

Actions

This Discussion