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Cisco Bug: CSCut40421 - Padding is not working for less than 64 bytes packets

Last Modified

Dec 06, 2018

Products (1)

  • Cisco Catalyst 6000 Series Switches

Known Affected Releases

15.1(2)SY2.1 15.1(2)SY5.1 15.2(1)SY

Description (partial)

Packet drops are seen when a small packet ( CRC + data + additional tag, e.g vlan,mpls,gre etc = 64 B) comes inside a switch and has to go out through a 10G/40G port after additional tag is removed. Packet should go out of the switch with a minimum size of 64 bytes. If the packet size is less than 64 bytes after removal of additional tags then switch should pad the packet.

This bug is applicable for egress traffic 10gig/40gig ports. Please check the list of affected linecards and versions below to verify exposure to this defect.

1. 64B Packet ingresses on trunk interface (60byte packet + 4 byte vlan tag) and egresses out l3 interface or access port , should be padded with 4 byte padding or
2. 64B packet ingress on mpls interface(60byte packet + 4 byte mpls label) and egress out as IP packet.
3. Same example holds good for GRE and other encapsulated packets as well.
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