Symptom
ISIS LSP PDU with size around 196~200bytes got silent dropped between SPP & Netio on Tomahawks linecard.
SPP debug shows NPH length of dropped PDU was set to wrong value "0f 1e". The expected NPH value should be "0f 0e". This is seen in 533 release, with tomahawk based line cards. ISIS LSP packets are getting silently lost in the software leading to LSP are not in sync.
Conditions
HW = Tomahawks LC
Size= 196-200B
Size 132 B
Protocol = ISIS
packet size 125-127B, 187-191B, 249-255B.
Multicast traffic
Further Problem Description
In tomahawk Based Line card, Fabric ASIC used is Tigershark and for multicast traffic of below size mentioned packets can run into the CRC errors and might be silently dropped in the software or hardware.
Tomahawk FIA (aka Tigershark) can run into CRC error and cause packet drop for mulitcast traffic when packet size falls into 125-127B, 187-191B, 249-255B. In this specific case, (196-200 bytes) + 17 byte of ISIS header + 36 bytes header falls into the last category.
