In a three-member Virtual Chassis setup (where one is a QFX5100-24s device), disabling and enabling one VCP port on the QFX5100-24s device is bringing down the other port, with a reboot required to recover both ports.
In this article, you understand the cause for the second port to go down and also learn about the solution to use to resolve the issue.
The three-member Virtual Chassis setup consists of two QFX5100-96s devices and one QFX5100-24s device wherein port 100 from each QFX5100-96s device is connected to the QFX5100-24s device. When VC port 1/2 on QFX5100-24s is disabled and then enabled, port 1/3 is brought down and port 1/2 does not come up.
{master:0} QFX5100-VC> show virtual-chassis vc-port localre: -------------------------------------------------------------------------- Interface Type Trunk Status Speed Neighbor or ID (mbps) ID Interface PIC / Port 0/100 Configured 6 Up 40000 2 vcp-255/1/3 0/96 Configured 5 Up 40000 1 vcp-255/0/96 0/97 Configured 5 Up 40000 1 vcp-255/0/97 0/98 Configured 6 Up 40000 2 vcp-255/1/1 fpc1: -------------------------------------------------------------------------- Interface Type Trunk Status Speed Neighbor or ID (mbps) ID Interface PIC / Port 0/100 Configured 6 Up 40000 2 vcp-255/1/2 0/96 Configured 5 Up 40000 0 vcp-255/0/96 0/97 Configured 5 Up 40000 0 vcp-255/0/97 0/98 Configured 6 Up 40000 2 vcp-255/1/0 fpc2: -------------------------------------------------------------------------- Interface Type Trunk Status Speed Neighbor or ID (mbps) ID Interface PIC / Port 1/0 Configured 6 Up 40000 1 vcp-255/0/98 1/1 Configured 5 Up 40000 0 vcp-255/0/98 1/2 Configured 6 Up 40000 1 vcp-255/0/100 1/3 Configured 5 Up 40000 0 vcp-255/0/100
QFX5100-VC> request virtual-chassis vc-port delete pic-slot 1 port 2 member 2 fpc2: -------------------------------------------------------------------------- Port deletion initiated, use cmd show virtual-chassis vc-port to verify QFX5100-VC> show virtual-chassis vc-port localre: -------------------------------------------------------------------------- Interface Type Trunk Status Speed Neighbor or ID (mbps) ID Interface PIC / Port 0/100 Configured 6 Up 40000 2 vcp-255/1/3 0/96 Configured 5 Up 40000 1 vcp-255/0/96 0/97 Configured 5 Up 40000 1 vcp-255/0/97 0/98 Configured 6 Up 40000 2 vcp-255/1/1 fpc1: -------------------------------------------------------------------------- Interface Type Trunk Status Speed Neighbor or ID (mbps) ID Interface PIC / Port 0/100 Configured -1 Down 40000 0/96 Configured 5 Up 40000 0 vcp-255/0/96 0/97 Configured 5 Up 40000 0 vcp-255/0/97 0/98 Configured -1 Up 40000 2 vcp-255/1/0 fpc2: -------------------------------------------------------------------------- Interface Type Trunk Status Speed Neighbor or ID (mbps) ID Interface PIC / Port 1/0 Configured -1 Up 40000 1 vcp-255/0/98 1/1 Configured 5 Up 40000 0 vcp-255/0/98 1/3 Configured 5 Up 40000 0 vcp-255/0/100 {master:0}
QFX5100-VC> request virtual-chassis vc-port set pic-slot 1 port 2 member 2 fpc2: -------------------------------------------------------------------------- Port conversion initiated, use show virtual-chassis vc-port to verify {master:0}
QFX5100-VC> show virtual-chassis vc-port localre: -------------------------------------------------------------------------- Interface Type Trunk Status Speed Neighbor or ID (mbps) ID Interface PIC / Port 0/100 Configured -1 Down 40000 0/96 Configured 5 Up 40000 1 vcp-255/0/96 0/97 Configured 5 Up 40000 1 vcp-255/0/97 0/98 Configured -1 Up 40000 2 vcp-255/1/1 fpc1: -------------------------------------------------------------------------- Interface Type Trunk Status Speed Neighbor or ID (mbps) ID Interface PIC / Port 0/100 Configured -1 Down 40000 0/96 Configured 5 Up 40000 0 vcp-255/0/96 0/97 Configured 5 Up 40000 0 vcp-255/0/97 0/98 Configured -1 Up 40000 2 vcp-255/1/0 fpc2: -------------------------------------------------------------------------- Interface Type Trunk Status Speed Neighbor or ID (mbps) ID Interface PIC / Port 1/0 Configured -1 Up 40000 1 vcp-255/0/98 1/1 Configured -1 Up 40000 0 vcp-255/0/98 1/2 Configured -1 Down 40000 1/3 Configured -1 Down 40000
When an interface goes down (moved from VCP to normal ports), auto-channelization is triggered, which brings down these ports.
To resolve this problem, you can disable auto-channelization either entirely or only on the required ports.
Disable auto-channelization on the desired ports:
set chassis fpc <fpc-slot> pic <pic-slot> port <port-num> channel-speed disable-auto-speed-detection
Disable auto-channelization entirely:
set chassis fpc <fpc-slot> auto-speed-detection disable