The Catalyst 4908G-L3 provides an aggregate throughput of close to 12 Mpps for Layer 3 switching (it performs at wire speed for its 8 interfaces yielding an aggregate of 11,904 Mpps.) These data rates apply not only to IP and IPX traffic but also to IP multicast and bridged traffic and are a result of using high-speed application-specific integrated circuit (ASIC) technology on each port to perform true Layer 3 switching. The Catalyst 4908G-L3 supports a high-performance architecture with 22 Gbps bandwidth. The switch fabric is capable of supporting all 8 Gigabit Ethernet ports simultaneously at wire speed.
Catalyst 4908G-L3 features at a glance:
The Catalyst 4908G-L3 provides a complete IP routing solution without sacrificing any of the services that are required to build a scalable network. The Catalyst 4908G-L3 is a feature-rich switch with full Cisco IOS implementation that allows network managers to continue to administer and manage their networks as they do today while scaling their backbone bandwidths to gigabit speeds. The Catalyst 4908G-L3 supports all the routing protocols that are used today in mid-sized networks. These protocols include:
In addition to these routing protocols, the Catalyst 4908G-L3 supports all the additional protocols necessary to build scalable, reliable networks, including:
The Catalyst 4908G-L3 Switch supports IP multicast at wire speeds across all its ports. As multicast applications such as Microsoft NetShow and NetMeeting become more widely deployed, end-to-end multicast support becomes increasingly important with multicast routing protocols that are integral to a consistent end-to-end multicast solution. The Catalyst 4908G-L3 supports both Protocol Independent Multicast (PIM) sparse and dense modes, and Distance Vector Multicast Routing Protocol (DVMRP) interoperability for legacy applications. The Catalyst 4908G-L3 provides support for IGMP, Versions 1 and 2, and CGMP server capabilities for integrating IP multicast support with Catalyst wiring closet switches. These protocols are necessary not only for IP multicast clients to join groups but also for efficient leave processing, which saves bandwidth and end-station CPU cycles.
The Catalyst 4908G-L3 has the ability to prevent security breaches via the use of both IP and IPX access lists. This is useful in preventing users from accessing certain applications or services. The Catalyst 4908G-L3 will support both inbound and outbound access lists on all its Gigabit Ethernet interfaces. These access lists can be defined similar to any Cisco IOS router as standard IPX access lists as well as standard and extended IP based access lists. Having both inbound and outbound control of packets on the Gigabit Ethernets allows Network Managers to prevent traffic both on egress as well as ingress.
The Catalyst 4908G-L3 incorporates a centralized non-blocking 22 Gigabit shared-memory switching fabric. The rich QoS capabilities of the switching fabric enable network managers to protect mission-critical applications by supporting delay-sensitive traffic, while managing bandwidth in the campus backbone. The switching fabric supports Per-Flow Queuing (PFQ), differentiated delay priorities using a WRR scheduler for delay-sensitive applications, and differentiated loss priorities for managing congestion and traffic policing and shaping. The fast packet memory embedded in the switching fabric is allocated dynamically on a per-queue (flow) basis. This dynamic allocation used in conjunction with user-defined queue thresholds and configurable queue scheduling weights ensures that time-sensitive traffic is handled properly with no packet loss. These thresholds and queuing weights can be dynamically adjusted with Cisco Assure Policy Networking, allowing an end-to-end QoS solution.
The Catalyst 4908G-L3 supports per-port input rate limiting,
output rate limiting, and traffic shaping on Gigabit Ethernet and Fast Ethernet interfaces. The per-port rate limiting feature provides the ability to rate limit the input and/or output traffic of a port. The traffic rate of the port is monitored. The conforming traffic is allowed, and the nonconforming traffic is dropped. The per-port shaping feature provides the ability to shape the output of a port. The output traffic rate of the port is monitored to verify that the traffic leaves the interface at the user-configured rate. When excess traffic comes into the switch, back pressure is applied from the modules to the switch fabric, and the excess traffic gets queued in the switch fabric. If the switch fabric queues overflow, the excess traffic is dropped. The minimum rate is 32 kbps, with a granularity of 32 kbps.