Cisco Cisco IOS Software Release 15.2(3)E

These release notes describe the features, modifications, and caveats for Cisco IOS Release 15.2(4)E on 
the Catalyst 4900M switch, the Catalyst 4948E Ethernet Switch, and the Catalyst 4948E-F Ethernet 
Switch.

Cisco Catalyst 4900M Series is a premium extension to the widely deployed Catalyst 4948 Series top of 
rack Ethernet switches for data center server racks. Optimized for ultimate deployment flexibility, the 
Catalyst 4900M Series can be deployed for 10/100/1000 server access with 1:1 uplink to downlink 
oversubscription, mix of 10/100/1000 and 10 Gigabit Ethernet servers or all 10 Gigabit Ethernet servers 
in the same rack. The Catalyst 4900M is a 320Gbps, 250Mpps, 2RU fixed configuration switch with 
8 fixed wire speed X2 ports on the base unit and 2 optional half card slots for deployment flexibility and 
investment protection. Low latency, scalable buffer memory and high availability with 1+1 hot 
swappable AC or DC power supplies and field replaceable fans optimize the Catalyst 4900M for any size 
of data center.

With Cisco IOS Release 12.2(54)XO, Cisco introduced the Catalyst 4948E Ethernet Switch, which is the 
first Cisco Catalyst E-Series data center switch built from the start to deliver class-leading, full-featured 
server-access switching. The switch offers forty-eight 10/100/1000-Gbps RJ45 downlink ports and four 
1/10 Gigabit Ethernet uplink ports and is designed to simplify data center architecture and operations by 
offering service provider-grade hardware and software in a one rack unit (1RU) form factor optimized 
for full-featured top-of-rack (ToR) data center deployments.

The Cisco Catalyst 4948E Ethernet Switch builds on the advanced technology of the Cisco Catalyst 4948 
Switches, the most deployed ToR switch in the industry, with more than 10 million ports deployed 
worldwide. The Cisco Catalyst E-Series doubles the uplink bandwidth and offers true front-to-back 
airflow with no side or top venting. Stringent airflow management reduces data center operating costs 
by providing strict hot-aisle and cold-aisle isolation. Exceptional reliability and serviceability are 
delivered with optional internal AC and DC 1+1 hot-swappable power supplies and a hot-swappable fan 
tray with redundant fans.

With Cisco IOS Software Release 12.2(54)WO, Cisco extended the widely deployed Cisco Catalyst® 
4948E Ethernet Switch to offer back-to-front airflow with the Cisco Catalyst 4948E-F Switch.