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Cisco Bug: CSCvv14062 - NEXUS 3548 MTC has IP unicast reachability from Sup to any direct connect end host

Last Modified

Oct 09, 2020

Products (1)

  • Cisco Nexus 3000 Series Switches

Known Affected Releases

7.0(3)I7(8) 9.3(5)

Description (partial)

One of the Neuxs 3548 across vPC peer-link can not reach the direct connected host behind the vPC port-channel. All IP unicast traffic that generated from CPU is involved. L2 traffic , L3 multicast and L3 broadcast works fine. We do see ARP is resolved and HSRP works fine.L2 forwarding for data packet that came outside the switch to the impact port-channel is also fine

TX counter did not increase for the impact Port-channel when we send the ping

LCND show INVALID packet and it constantly increasing.

One of the Nexus across vPC is not reachable to direct connected device. All Control-plane generated IP unicast packet are impacted.  L2 forwarding is fine on data plane. TX counter never increased.

Two vPC domain interconnect via back to back vPC setup. All four device across two peer-link are nexus 3548. For each domain, Multiple sever and few network device are directly connected via vPC port-channel to each of the Nexus. The issue is triggered after  downgrade from 9.3.3 to i7(8). Upgrade to 9.3.5 will not help.  Only host devices are impacted
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