Cisco Nexus 3550-T NX-OS Release Notes, Release 10.2(3t)

October 25, 2022

A mandatory SMU patch for release 10.2(3t) became available. For details, see Cisco 3550-T NX-OS Patch Release Notes, Release 10.2(3t).

September 16, 2022

Release 10.2(3t) became available.

Support for virtual port channels (vPC)

vPCs enable links that are physically connected to two different Cisco Nexus 3550-T Series devices to appear as a single port channel by a third device. The third device can be a switch, server, or any other networking device that supports port channels. A vPC can provide Layer 2 multi-pathing, which allows you to create redundancy and increase the bisectional bandwidth by enabling multiple parallel paths between nodes & allowing load balancing traffic.

For details, see the Configuring vPCs chapter in the Cisco Nexus  3550-T Interfaces Configuration Guide, Release 10.2(x).

Unidirectional Link Detection (UDLD)

The UDLD protocol allows devices that are connected through fiber-optic or copper (for example, Category 5 cabling) Ethernet cables to monitor the physical configuration of the cables and detect when a unidirectional link exists.

For details, see the Unidirectional Link Detection chapter in the Cisco Nexus 3550-T Interfaces Configuration Guide, Release 10.2(x).

Network address translation (NAT) support on switch virtual interfaces (SVI)

 NAT enables the router to change the IP source or destination address of the packets. Support extended for switch virtual interfaces.

For details, see the Static NAT chapter in the Cisco Nexus 3550-T Interfaces Configuration Guide, Release 10.2(x).

VRRP Support on SVI

VRRP allows for transparent failover at the first-hop IP router by configuring a group of routers to share a virtual IP address. VRRP selects a master router in that group to handle all packets for the virtual IP address. The remaining routers are in standby and take over if the master router fails. Support extended for SVI interfaces.

For details, see the Configuring VRRP chapter in the Cisco Nexus 3550-T Unicast Routing Configuration Guide, Release 10.2(x).

Layer 2 Multicast Enhancements

Enables the Cisco Nexus 3550-T switch to forward packets on L2 ports. Packets are forwarded in a cut-through manner; hence IGMP reports are flooded to other receivers including other routers/queriers in VLAN.

For details, see the Configuring IGMP Snooping chapter in the Cisco Nexus 3550-T Multicast Routing Configuration Guide, Release 10.2(x).

Layer 3 Multicast Enhancements

Enables the Cisco Nexus 3550-T to operate as a first hop router (FHR) for PIM-sparse mode.

For details, see the Configuring PIM chapter in the Cisco Nexus 3550-T Multicast Routing Configuration Guide, Release 10.2(x).

Per VLAN Rapid Spanning Tree Protocol (PVRSTP)

Support for per port, per VLAN STP state. Default spanning-tree mode is changed to RSTP from MSTP. RSTP and MSTP with multiple instances are supported.

For details, see the Cisco Nexus  3550-T Layer 2 Switching Configuration Guide, Release 10.2(x).

High-Precision Timestamping

Enables high-precision timestamping (HPT) on packets ingressing on a Cisco Nexus N3550-T switch. The time-stamp corresponds to the time the packet has arrived on a N3550-T front-panel port. Timestamping is supported for data packets going through the fabric. The feature can be enabled on any egress port. Also known as Rx timestamping.

For details, see the Configuring HPT chapter in the Cisco Nexus 3550-T System Management Configuration Guide, Release 10.2(x).

ACL Support on SVI

Enables you to configure the rules that when matched, will let the packets pass through an interface. Support extended for SVI interfaces.

For details, see the Configuring IP ACLs chapter in the Cisco Nexus 3550-T Security Configuration Guide, Release 10.2(x).

Port Mirroring (SPAN support)

SPAN analyzes all the traffic between source ports by directing the SPAN session traffic to a destination port with an external analyzer attached to it.

For details, see the Configuring SPAN chapter in the Cisco Nexus 3550-T System Management Configuration Guide, Release 10.2(x).

VRF Support

All IP-based features are VRF-aware. Support for VRF on OSPFv2, BGP, PIM. See the Configuring Layer 3 Virtualization chapter in the Cisco Nexus 3550-T Unicast Routing Configuration Guide, Release 10.2(x).

Multicast Filtering

Enables configuration of multicast filters for PIM/IGMP joins on interfaces and VLANs.

For details, see the Configuring PIM chapter in the Cisco Nexus 3550-T Multicast Routing Configuration Guide, Release 10.2(x).

PTP Boundary Clock

PTP is a time synchronization protocol. PTP is supported on IPv4 multicast, two-step master, version-2 only with boundary clock functionality.

For details, see the Configuring PTP chapter in the Cisco Nexus 3550-T System Management Configuration Guide, Release 10.2(x).

Secure Erase

The secure erase feature erases all customer information for Nexus 3550-T switches. Secure Erase is an operation to remove all the identifiable customer information on Cisco NX-OS devices in conditions of product removal due to Return Merchandise Authorization (RMA), or upgrade or replacement, or system end-of-life.

For details, see the Secure Erase chapter in the Cisco Nexus 3550-T System Management Configuration Guide, Release 10.2(x).

Multicast ACL for rendezvous points (RP)

This feature enables the configuration of multicast ACL(s) for RPs in IPv4 networks. You can create (*,G) trees determined by the policy for a given multicast group.

For details, see the Configuring Multicast ACL for RPs chapter in the Cisco Nexus 3550-T Multicast Routing Configuration Guide, Release 10.2(x).

CSCvy92285

Headline: Router-on-stick configuration L3 Unicast getting dropped.

Symptoms: L3 Unicast traffic may get dropped in a corner-case scenario.

Conditions: Traffic Ingresses and is expected to Egress out of the same L2 trunk Port-Channel interface after getting routed between SVIs.

Workaround: None

 CSCwc68101

Headline: N35-T-48X to N9K-C93180YC-FX Connections: Observing extra reset with reload on multiple links.

Symptom: An extra interface reset is reported on a few interfaces on N35-T-48X post reload.

Conditions:

Workaround: None

CSCwc98443

Headline: TypeError: unsupported operand type while collecting show tech detail.

Symptom: A python script error may be seen on executing 'show tech-support detail'. The command continues to collect all the required logs from the system.

Conditions: 'show tech-support details' command is executed.

Workaround: None.

 CSCwa70130

Headline: Exablaze: L3 Routing across the ULL network in the Colo is unstable due to Mac out-of-sync issue.

Symptom: Host to gateway (SVI IP) ping stops working after certain triggers

Conditions:

Workaround: Issue the 'clear mac address-table dynamic' command

CSCwb57272

Headline: N3550-T static NAT does not translate TCP flow.

Symptom: TCP flow times out.

Conditions: TCP flows is going via N3550-T doing static NAT.

Workaround: N/A

CSCvz73310

Headline: Dynamic Nat Entries replicated when shutting L3backup Links in same quad leading to table exhaustion.

Symptom: Primary link flap (shut/no shut) with NAT or ACL can cause NAT/ACL HW table exhaustion.

Conditions:

Workaround:

CSCvz10166

Headline: SFP 1gig mgmt interface didnt come up.

Symptom: Link does not come up when connected to the 1GbE SFP management port. Management connectivity is not established.

Conditions: Any supported transceiver connected to the 1GbE SFP management port.

Workaround: None. Use RJ45 port for management connectivity on N3550-T.

CSCwc54808

Headline: Unknown Multicast packets are not flooded to ports on same vlan.

Symptom: Multicast packets received when "no ip igmp snooping" is configured are not flooded in the VLAN

Conditions: "no ip igmp snooping” configured on VLAN

Workaround: None