Input & CRC errors between Blade and Nexus 5596

[dbertinetti]

When I connect the blade WS-CBS3012-IBM-I  with version 12.2(52)SE (CBS31X0-UNIVERSAL-M) against a Nexus 5596UP(n5000-uk9.5.0.3.N2.1)  with GLC-T interface I have packet loss and CRC on the blade. The amount of CRC and input errors are identical.

The both configuration are:

Nexus 5596

interface Ethernet1/45
switchport mode trunk
switchport trunk allowed vlan 32,100,933-935,937-938,940-941,944-945
speed 1000
duplex full

N5K-05-MTZ# sh int et1/45 transceiver
Ethernet1/45
transceiver is present
type is 1000base-T
name is CISCO-AVAGO
part number is ABCU-5710RZ-CS4
revision is B2
serial number is AGM1840250E
nominal bitrate is 1300 MBit/sec
Link length supported for copper is 100 m
cisco id is --
cisco extended id number is 4

WS-CBS3012-IBM-I

interface GigabitEthernet0/18
description PP 54 - BR-SW-S-DC2-01 Gi1/38 - IP 180.166.32.5
switchport trunk allowed vlan 32,100,933-935,937,938,940,941,944,945
switchport mode trunk
end

If I connect the same blade with the same configuration against a Catalyst 4500, it works well ( The blade no account input errors/CRC)

Does anyone know why this happens?

Thanks in advance

[jvaronaa]

Nexus switches use a different forwarding architecture, so they might not check for CRC errors and forward packets with such errors, on the other hand, blade switches are based on Catalyst architecture, which does perform a frame check before receiving it, and will drop it on the inbound port, which looks like what the blade is doing. With the 4500 you'll not see this problem because it is also a catalyst switch and will never forward such packet (unless its own interface or line card is damaged).

have you called TAC? maybe the nexus team can assist you tracking this on the Nexus switch.