Traffic monitoring

As we've often discussed here, the advent of IP-enhanced frame relay and ATM services is making it increasingly difficult to tell the difference between an IP service and a frame relay or ATM service. But a constant remains: the need to monitor your traffic, especially for service-level agreement verification. After all, having an SLA that you can't measure isn't much better than having no SLA at all.

Visual Networks' recent announcement of Version 7.1 of its Visual UpTime performance monitoring software and a High-Speed Serial Interface (HSSI)-based IP transport solution for IP VPNs, scheduled to ship in the third quarter, impacts customer networks on a couple of fronts. Here, we'll discuss the impact on the physical network layer.

The IP monitoring capabilities of the Visual UpTime T-1 DSU/CSU have been added to Visual's high-speed Analysis Service Element probe device, which has a HSSI interface. This permits monitoring of circuits that are using a HSSI interface on the router and a HSSI interface on, perhaps, an inverse multiplexer.

We see this as being especially important for host sites that require more than a T-1's worth of bandwidth but still do not have a need for a full T-3 circuit. As DSL, cable and wireless technologies augment traditional T-1 interfaces at remote sites, the need for analyzing multiple T-1s will continue to grow. An advantage of the HSSI interface is that the performance is analyzed as a single information stream instead of multiple information streams. This puts to rest any religious arguments about whether Multilink Frame Relay, Inverse Multiplexing over ATM or Multilink PPP is a better inverse multiplexing capability. By analyzing the composite stream, the underlying technology becomes a moot point.

Carriers beef up service-level agreements
Network World, 05/06/02

Cisco fortifies remote branch routers
Network World, 05/06/02

Steven Taylor, consultant and broadband packet evangelist, and Joanie Wexler, an independent networking technology editor and writer, team up to bring you this analysis and commentary. Taylor specializes in education and market analysis, and Wexler adds incisive reporting and research. For more detailed information on most of the topics discussed in this newsletter, connect to www.webtorials.com, the first Web site dedicated exclusively to market studies and technology tutorials in the Broadband Packet areas of Frame Relay, ATM, and IP.

Feedback and additional topic ideas are welcome. Please contact taylor@webtorials.com or joanie@jwexler.com.

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