The Cisco Catalyst
4900M Switch is designed for data center network top-of-rack switching and
midmarket collapsed core and aggregation layer deployment. Optimized for ultimate deployment flexibility for the data
center, the Cisco Catalyst 4900M can be deployed for 10/100/1000 or 1/10GBASE-T server access with 1:1 uplink-todownlink
oversubscription and environments with a mix of 10/100/1000 and 10 Gigabit Ethernet servers or all 10
Gigabit Ethernet servers.
The Cisco Catalyst 4900M is a 320-Gbps, 250-million-packets-per-second (mpps), two-rack-unit (2RU) fixedconfiguration
switch with eight fixed wire-speed X2 ports on the base unit and two 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 a field-replaceable fan tray optimize the Cisco Catalyst 4900M for data
centers of any size.
For the midmarket collapsed core and aggregation layer and in the branch office, the Cisco Catalyst 4900M provides
an ideal solution for space-constrained deployments that require high-performance wire-speed services and high
availability. With the unique semifixed architecture and support of the Cisco TwinGig Converter Module, the Cisco
Catalyst 4900M can be used in a collapsed core and aggregation layer LAN deployment, providing the flexibility to
deploy Gigabit Ethernet now and cost-effectively migrate to 10 Gigabit Ethernet as requirements change.
The Cisco Catalyst 4900M configuration provides wire-speed connection, buffers to handle bursty traffic, and a
comprehensive set of Layer 3 features required at the collapsed core and aggregation layer of the network. The
Cisco Catalyst 4900M also supports a suite of ease-of-management features to simplify operations.

The Cisco Catalyst 4900M half cards provide a wide variety of combinations of Gigabit Ethernet and 10 Gigabit
Ethernet media types. The base unit can accommodate up to two of the half cards shown in Figures 2, 3, 4, and 5, in
any combination.

– Layer 2 switch ports and VLAN trunks
– IEEE 802.1Q VLAN encapsulation
– Dynamic Trunking Protocol (DTP)
– VLAN Trunking Protocol (VTP) and VTP domains
– VTP pruning
– VTPv3
– Port security on trunk port
– Q-in-Q passthrough
– Support for 4096 VLANs per switch
– PVST+ and Per-VLAN Rapid Spanning-Tree Protocol (PVRST)
– Spanning Tree PortFast and PortFast guard
– Spanning Tree UplinkFast and BackboneFast
– IEEE 802.1s
– IEEE 802.1w
– IEEE 802.3ad
– Spanning Tree root guard
– Cisco Discovery Protocol
– Internet Group Management Protocol (IGMP) versions 1, 2, and 3 snooping
– IPv6 Multicast Listener Discovery (MLD) snooping
– Cisco EtherChannel technology, Cisco Fast EtherChannel technology, and Cisco Gigabit EtherChannel
technology across half cards and base unit
– Port Aggregation Protocol (PAgP)
– Link Aggregation Control Protocol (LACP)
– Unidirectional link detection (UDLD) and aggressive UDLD
– Jumbo frames (up to 9216 bytes)
– Baby Giants (up to 1600 bytes)
– Storm control (formally known as broadcast and multicast suppression)
– Forced 10/100 autonegotiation
– Bridge protocol data unit (BPDU) guard
– FlexLink and FlexLink with VLAN Load Balancing
– IEEE 802.1ab Link Layer Discovery Protocol (LLDP) and 802.1ab LLDP Media Endpoint Devices (LLDPMED)
– Resilient Ethernet Protocol (REP)
– IEEE 802.1Q tunneling (Q-in-Q) in hardware
– Layer 2 protocol tunneling