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Giants errors seen on Cisco 6807 VSS switch

siddu.s.m
Level 1
Level 1

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

2 Accepted Solutions

Accepted Solutions

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

View solution in original post

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

View solution in original post

4 Replies 4

Reza Sharifi
Hall of Fame
Hall of Fame

Hi,

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

Does this only happen when you change MTU to 9216?

HTH

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

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

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

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