Datacom Systems VS series SPAN, SS series SPAN manual Analyzing/Monitoring Gigabit EtherChannel

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DAISY: DAISY ports IN and OUT are RJ45 connectors cabled to the next aggregator. The LED Display Code Table deciphers the RJ45 jacks with integrated LEDs that display line status and line speed of each port.

Analyzing/Monitoring Gigabit EtherChannel

CONCERN: The popularity of web-based services has increased bandwidth consumption. An increase in bandwidth consumption has also brought increased network problems. The increase in traffic and accompanying problems are often seen on the backbone of networks where mis- sion critical applications and services must travel. In an effort to maximize network perfor- mance, meet the current and future needs of users, and ensure uptime, bandwidth and fault-tol- erance have become a primary focus of networking professionals.

To solve many bandwidth and fault-tolerance problems, network professionals have imple- mented Gigabit EtherChannel in their network. Because IT Managers are often working with flat budgets and must utilize existing equipment and cabling, Gigabit EtherChannel is a com- mon solution used to increase bandwidth, improve load-balancing, and create fault-tolerance.

Common Gigabit EtherChannel configurations combine up to eight Gigabit Ethernet segments into a single, logical channel between switches, routers, and servers. For example, a four-link Gigabit EtherChannel takes four Gigabit full duplex links (a total bandwidth 2000 MB) and combines them into one virtual link (a total bandwidth of 8000 MB), effectively quadrupling bandwidth. These links are managed and load balanced by Port Aggregation Protocol (PAgP). If anyone of the four links fails, PAgP will automatically redirect and load balance the remain- ing three links.

Because traffic in a Gigabit EtherChannel implementation is load balanced, packets are dis- tributed across several different physical links. Often, traffic transmits on one segment and receives on another. This makes network analysis and monitoring especially challenging. If an analyzer or monitoring device is put on only one physical link, it will not see the entire con- versation. Most analyzers and monitoring devices also cannot view EtherChannel traffic.

SOLUTION: Because Gigabit EtherChannel is comprised of multiple physical links, most ana- lyzers and monitoring devices cannot provide complete monitoring, troubleshooting, and diag- nosis of the most critical parts of the network. Up until now, the few solutions that exist have been very expensive, not compatible with existing tools, or have been time-consuming to administer.

SPAN and Multi-Link Aggregators/Regenerators • USERguide