The increasing deployment of switched Ethernet to the desktop can be attributed to the proliferation of bandwidth hungry intranet applications that drive demand for more and more bandwidth. Web browsing, and any-to-any communications of new intranet applications such as video to the desktop and collaborative white-boarding are increasing the need for scalable bandwidth within the core of campus networks, while mission-critical applications call for resilient network designs. With the wide deployment of switched Fast Ethernet in the campus, users are awaiting delivery of standards-based Gigabit Ethernet products to scale performance across their backbones.
Cisco's Fast EtherChannel technology builds upon standards-based 802.3 full-duplex Fast Ethernet to provide network managers a reliable high-speed solution for the campus network backbone. Fast EtherChannel provides bandwidth scalability within the campus by providing increments of 200 Mbps to 800 Mbps with multigigabit capacity in the future. Fast EtherChannel technology not only solves the immediate problem of scaling bandwidth within the network backbone today, but also paves the path for an evolution to standards-based Gigabit Ethernet and beyond, because Fast EtherChannel technology can be applied to support Gigabit EtherChannel.
Fast EtherChannel provides a solution for network managers who require higher bandwidth between servers, routers, and switches than Fast Ethernet technology can currently provide. Cisco is committed to providing its customers with smooth evolution to Gigabit Ethernet bandwidth and beyond, and, with Gigabit Ethernet technology, Cisco will extend Fast EtherChannel to scale to provide multigigabit backbones in the future.
Fast EtherChannel provides scalable bandwidth in increments without having to deploy pre-standard Gigabit Ethernet approaches today and replace them tomorrow. Fast EtherChannel provides the following benefits:
- Standards based---Fast EtherChannel builds upon IEEE 802.3-compliant Fast Ethernet by grouping multiple full duplex point-to-point links together. Fast EtherChannel uses the industry standard 802.3 mechanisms for full duplex auto-negotiation and auto-sensing.
- Multiple Platforms---Fast EtherChannel is flexible and can be used anywhere in the network where bottlenecks are likely to occur. Fast EtherChannel can be leveraged in network designs to increase bandwidth between switches, between routers and switches, as well as providing scalable bandwidth for network servers, such as large UNIX servers or PC-based Web servers.
- Flexible Incremental Bandwidth---Fast EtherChannel provides bandwidth aggregation in multiples of 200 Mbps, with multiples of Gigabit Ethernet in the future. For example, network managers can deploy Fast EtherChannel consisting of pairs of full-duplex Fast Ethernets to provide 400+ Mbps between the wiring closet and the data center, while in the data center bandwidths of up to 800 Mbps can be provided between servers and the network backbone to provide large amounts of scalable incremental bandwidth.
- Load Balancing---Fast EtherChannel is composed of multiple Fast Ethernet links and is capable of load balancing traffic across those links. Unicast, broadcast, and multicast traffic is evenly distributed across the links providing higher performance and redundant parallel paths. In the event of a link failure, traffic is redirected to remaining links within the channel without user intervention.
- Resiliency and Fast Convergence---Fast EtherChannel provides automatic recovery for loss of a link by redistributing loads across remaining links. If a link does fail, Fast EtherChannel will redirect traffic from the failed link to the remaining links in less than a second. This convergence is transparent to the end user---no host protocol timers expire, therefore no sessions are dropped.
- Ease of Management---Fast EtherChannel leverages the experience and know-how developed over the years in troubleshooting and maintaining Ethernet and Fast Ethernet networks. Existing network probes can be used for traffic management and troubleshooting, and existing management applications such as CiscoView and TrafficDirector will be leveraged to support Fast EtherChannel.
- Transparent to Network Applications---Fast EtherChannel does not require any changes to networked applications. When Fast EtherChannel is used within the campus, switches and routers provide load balancing across multiple links transparently to network users. For support of Fast EtherChannel on enterprise-class servers and NIC cards, smart software drivers can coordinate distribution of loads across multiple network interfaces.
- Compatible with Cisco IOS---Fast EtherChannel connections are fully compatible with Cisco IOS virtual LAN and routing technologies. The Inter-Switch Link (ISL) VLAN trunking protocol can carry multiple VLANs across a Fast EtherChannel, and routers attached to Fast EtherChannel trunks can provide full multiprotocol routing with support for hot standby using HSRP.
- Gigabit Ethernet Ready---Fast EtherChannel technology is Gigabit Ethernet ready. Fast EtherChannel allows network managers to deploy networks today that scale smoothly with the availability of standards-based Gigabit Ethernet and beyond with future Gigabit EtherChannel.
Fast EtherChannel is a trunking technology based on grouping together multiple full-duplex 802.3 Fast Ethernets to provide fault-tolerant high-speed links between switches, routers, and servers. Fast EtherChannel is based on proven industry standard technology---it has been extended from the EtherChannel technology offered by Kalpana in its switches in the early 90s, and provides load sharing across multiple Fast Ethernet links while providing redundancy and sub-second convergence times.
Fast EtherChannel consists of the following key elements:
- Fast Ethernet Links---Fast EtherChannels can be composed of two to four industry-standard Fast Ethernet links to provide load sharing of traffic with up to 800 Mbps of usable bandwidth. Fast EtherChannels can interconnect LAN switches, routers, servers, and clients. Since its load balancing is integrated with the Catalyst 5000 families LAN switch architectures, there is no performance degradation for adding links to a channel---high throughput and low latencies can be maintained while gaining more total available bandwidth. Fast EtherChannel provides link resiliency within a channel---if links should fail the traffic is immediately directed to the remaining links. Finally, Fast EtherChannel is not dependent on any type of media---it can be used with Fast Ethernet running on existing Unshielded Twisted Pair (UTP) wiring, or single mode and multimode fiber.
- Fast EtherChannel is available on Cisco 7500 routers with Fast Ethernet Interface Processors (FEIP),---Versatile Interface Processor (VIP2) Port Adapters or any combination of the two. Fast EtherChannel provides increased bandwidth and resiliency between Cisco 7500 routers and Cisco Catalyst switches, and is available with IOS release 11.1(14)CA for load sharing of IP traffic. As primarily a Layer 3 device, the router will load share transmitted packets across a Fast EtherChannel group based upon source and destination IP address, and for IP multicast and broadcast traffic, the load balancing will be based on source IP address. Future releases of Cisco IOS will support load sharing for IPX and AppleTalk, as well as Spanning-Tree Protocol (STP), Hot Standby Router Protocol (HSRP) and distributed VIP2 support.
- Redundancy---Fast EtherChannel does not require the use of 802.1D Spanning-Tree Protocol (STP) to maintain topology state within the channel; rather it uses a peer-to- peer control protocol that provides autoconfiguration and sub-second convergence times for parallel links, yet allows higher-level protocols such as STP, or existing routing protocols, to maintain topology. This approach allows Fast EtherChannel to leverage the recovery features of the network without adding complexity or creating incompatibilities with third-party equipment or software. Since the STP operation is completely standards based, network managers can leverage their existing network topologies, augmenting bandwidth by installing Fast EtherChannel where single Fast Ethernet links were previously installed.
- Management---Fast EtherChannel is easily configured by a Command Line Interface or by SNMP management applications such as CiscoWorks. A network manager simply needs to identify and define the number of ports that will make up the channel and then connect the devices. CiscoWorks for Switched Internetworks will graphically display Fast EtherChannels between devices as well as collect statistics for both individual Fast Ethernet links within the channel as well as aggregate statistics for the Fast EtherChannel. An integral benefit of Fast EtherChannel is the ability to detect, report, and prevent the use of incorrectly paired interfaces within the channel. These may include interfaces that are not configured for full-duplex operation, have mismatched link speeds, or are incorrectly wired. Consistency checks are completed before the activation of a channel to ensure network integrity.
The following diagrams show some common applications of Fast EtherChannel and how they solve the bandwidth requirements of today's networks.
Figure 1 shows a network using Fast EtherChannel where the bandwidth between the wiring closets and the data center has been doubled from 200 Mbps to 400 Mbps. In addition to the increased bandwidth, the resiliency within the channel provides for sub-second convergence if one of the links should fail.
Figure 1: Scaling performance between wiring closets and data center
Figure 2 shows a topology where the network manager has increased bandwidth between the data center and the wiring closet to an aggregate of 800 Mbps but has also used the physical diversity of the fiber plant to decrease the chances of a network outage. Using a Fast EtherChannel comprised of 4 Fast Ethernets, 2 fiber runs on the east side of the building provide 400 Mbps, with the west side of the building providing the remaining 400 Mbps. In this example, in the event of a fiber cut on one side of the building, the remaining side will pick up the traffic in less than a second, without any session losses observed by the clients in the wiring closet.
Figure 2: Scaling bandwidth with resilience
Figure 3 shows a configuration where a switch has been configured with two separate Fast EtherChannels consisting of two links each. Since these are separate channels, Spanning Tree will block the second channel to avoid the looped topology. This design is applicable where Fast EtherChannels are resident on separate line cards within the switch for resiliency.
Figure 3: Resilience with Fast EtherChannel using Spanning-Tree Protocol
Figure 4 shows a complete network design based on Fast EtherChannel. As in the previous examples, links from the wiring closets are brought into the data center using 400 Mbps channels, providing bandwidth and resiliency. In the Data Center, routers are interconnected with Fast EtherChannel providing performance increases by having more bandwidth available to route between subnets. Here the router is configured with two dual-link Fast EtherChannels to provide 400 Mbps of bandwidth on each subnet. The Fast EtherChannel provides load balancing across two links within the channel based on IP addresses, and the links within the channel can use ISL encapsulation for support of multiple subnets per link. The last component in this network design is a server attached via a four-link Fast EtherChannel, which provides 800 Mbps of bandwidth to the network. Typical platforms that would require such bandwidth would be high-end Pentium-pro servers, enterprise servers and high-end graphics imaging and rendering servers. As can be seen in Figure 4 the server is connected via a multiple-link Fast EtherChannel, which is an excellent match for the bandwidth needs of the locally attached users and those users serviced via the router.
Figure 4: Fast EtherChannel interconnecting Servers, Switches and Routers across the campus
Fast EtherChannel is a technology-leveraging, standards- based Fast Ethernet used in parallel to provide the additional bandwidth network backbones require today. It is an extension of EtherChannel applied to Fast Ethernet and is readily adaptable in the future to provide Gigabit EtherChannel as Gigabit Ethernet standardization is completed. In the interim, it provides flexible, scalable bandwidth with resiliency and load sharing across links for switches, router interfaces and servers. Fast EtherChannel provides the tools for network managers to build high-speed solutions today for their campus backbones, while leveraging their existing cabling and network device infrastructure. Cisco's strategy is to extend EtherChannel technology to Gigabit Ethernet upon its standardization.
Table 1: Cisco Fast EtherChannel Road Map
| Phase
| Features
| Capabilities
| Benefits
|
|---|
Phase I
| Fast EtherChannel on Catalyst 5000 and Cisco 7500 Routers 11.1(14)CA
| Scalable link bandwidths up to 800 Mbps between switches, routers, hosts
| Smooth migration toward gigabit-link bandwidths over existing Fast Ethernet cabling
|
Phase II
| Advanced Cisco IOS switch software features (e.g., PAgP)
| Automatic link configuration and failover recovery
| Resilient and easy-to-manage network topologies
|
Future
| Gigabit EtherChannel
| Link bandwidths of 2000 Mbps and higher
| Aggregation of multigigabit campus backbones
|
Posted: Mon Jul 3 04:41:22 PDT 2000
All contents copyright © 1992--2000 Cisco Systems, Inc. Important Notices and Privacy Statement.
