Giants errors seen on Cisco 6807 VSS switch

[siddu.s.m]

Hi Team,

We are observing Giants errors 6807-VSS interfaces which are connecting to OTV vdc.

We have a OTV setup on N-7710 switches. Join interfaces are connecting to Cisco 6807 switches in a L3 port-channel.

We have set MTU of 9216 in both side interfaces connecting between N-7710 and Cisco 6807. For OTV L2 interfaces MTU is set as 9160.

We are observing errors only on 6807-VSS which are connecting to OTV vdc but not observing any error on N7710 side.

Can some one help me here to resolve the issue.

Thanks in advance.

.... Sid

[Reza Sharifi]

Hi,

What type of card do you have installed on the 6807?

Does this only happen when you change MTU to 9216?

HTH

[siddu.s.m]

Hi,

We are using card WS-X6904-40G.

We have recently implemented this , we have not got any chance to change MTU and check.

My query is that does Giants packets get dropped or it is a forwarded. I can see counter increasing in thousands per second.

.... Sid

[Reza Sharifi · Accepted solution]

Hi,

Do you have any network issues causing by these giant packets?

Here is some info on MTU and giant frames.

Term Definitions

• MTU: MTU is short for Maximum Transmission Unit, the largest physical packet size, measured in bytes, that a network can transmit. Any messages larger than the MTU are divided into smaller packets before transmission.

• Jumbo: Jumbo frames are frames that are bigger than the standard Ethernet frame size, which is 1518 bytes (including Layer 2 (L2) header and FCS). The definition of frame size is vendor-dependent, as these are not part of the IEEE standard.

• Baby giants: The baby giants feature allows a switch to pass or forward packets that are slightly larger than the IEEE Ethernet MTU. Otherwise, the switch declares big frames as oversize and discards them.

• http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6000-series-switches/24048-148.html

[Tausif Gaddi · Accepted solution]

A maximum transmission unit (MTU) is the largest size packet or frame, specified in octets (eight-bit bytes), that can be sent in a packet- or frame-based network such as the Internet. The Internet's Transmission Control Protocol (TCP) uses the MTU to determine the maximum size of each packet in any transmission.

Please refer Jumbo/Giant Frame Support on Catalyst Switches Configuration Example on mentioned link
http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6000-series-switches/24048-148.html