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New Member

vPC trouble - link flapping between C3750 stack and Nexus 5596

Hi All,

I have configured 1 vPC's between 2 Nexus 5596 and 1 stack C3750 switch. The links in the stack are distributed over both members.

Gi1/1/1  -> Eth 1/44  NX 5596-02

Gi 2/1/1 -> Eth 1/45  NX 5596-02

Gi 1/1/2 -> Eth 1/46  NX 5596-01

Gi 2/1/2 -> Eth 1/47  NX 5596-01

The same logic is for another stack C3750 to the same pair of Nexus 5596 switches.

The problem is that the links from the vPCs keep flapping at random moments - 1-2 times per hour.

The network is not loaded at this time and the same issue is on both vPC's.

the flaps in the nexus 5596 looks like this

%ETH_PORT_CHANNEL-5-PORT_DOWN: port-channel108: Ethernet1/44 is down

%ETH_PORT_CHANNEL-5-FOP_CHANGED: port-channel108: first operational port changed from Ethernet1/44 to Ethernet1/45

%ETHPORT-5-IF_DOWN_INITIALIZING: Interface Ethernet1/44 is down (Initializing)

%ETH_PORT_CHANNEL-5-PORT_UP: port-channel108: Ethernet1/44 is up

%ETHPORT-5-IF_UP: Interface Ethernet1/44 is up in mode trunk

On the stack is just up/down the pair interface.

I started few debugs on the stack and captured the folowing output:

C3750X-02#im_if_stack_relationship_add: Posting the ACP job for stack add for 5018.10902

im_if_stack_relationship_add: Posted the ACP job for stack add successfully

im_add_ifstackentry: higher_if_index = 5018 lower_if_index = 10902

im_add_ifstackentry: Failed to delete nolayerelem from NoLowerLayerTree for higher_ifIndex = 5018

im_add_ifstackentry: Failed to delete nolayerelem from NoHigherLayerTree for lower_ifIndex = 10902

im_add_ifstackentry: Deleted nolayerelems from NoHigherLayerTree and NoLowerLayerTree

im_add_ifstackentry: Failed to insert stackelem into StackTree

Jul 12 03:35:26.122: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet2/1/2, changed state to downim_if_stack_relationship_add: Posting the ACP job for stack add for 5018.10902

im_if_stack_relationship_add: Posted the ACP job for stack add successfully

im_add_ifstackentry: higher_if_index = 5018 lower_if_index = 10902

im_add_ifstackentry: Failed to delete nolayerelem from NoLowerLayerTree for higher_ifIndex = 5018

im_add_ifstackentry: Failed to delete nolayerelem from NoHigherLayerTree for lower_ifIndex = 10902

im_add_ifstackentry: Deleted nolayerelems from NoHigherLayerTree and NoLowerLayerTree

im_add_ifstackentry: Failed to insert stackelem into StackTree

Jul 12 03:35:29.058: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet2/1/2, changed state to up

Do someone have any idea what happens here ?

The configuration is ok because i have another vPC connected to FEX's and is working fine.

Kind regards,

1 REPLY
New Member

vPC trouble - link flapping between C3750 stack and Nexus 5596

Hello,

Problem solved after  upgrade to the last version of NX OS  6.0.2.N2.3

BR,

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