Pointing A Finger At Network Management Point Products In our attempt to mirror ports from one switch to the monitor port on another switch, we lost communications with the switch that the probe was attached to. This gave us an opportunity to use Status Watch to find our port assignment, or, in this case, lack thereof. We were able to determine that we were no longer attached to the switch, but we were forced to use a VT220 terminal directly connected to the switch to fix the problem. Once fixed, it took some time for Transcend's database to synchronize with the actual VLAN setup on the switch. Once it did, we were able to map traffic from one switch to a probe port on another switch easily. 3Com was the only vendor to supply us with a multiport full-duplex 100-Mbps probe. When in full-duplex mode, the probe used the two ports in pass-through mode. When monitoring half-duplex segments, each port could monitor a different segment. However, all of this is manageable through one IP address assigned to any of the ports. Distributed Remote Monitoring (dRMON) is a switched traffic monitoring strategy unique to 3Com. It basically amounts to RMON on 3Com XL 10/100 network interface cards. Data sent to the station is monitored by the NIC, and statistics are sent to a Windows NT Server running EdgeMonitor. Because the NIC reports only on traffic destined for it, deployment in a shared environment requires that all devices run dRMON to achieve accurate statistics. 3Com claims that all nine groups of RMON are available across its entire switch product line. Each broadcast domain will require an EdgeMonitor Server, which made us wonder how it would work in a Layer 3 VLAN configuration, where a single MAC VLAN creates the domain. Cisco Systems Cisc o Works for Switched Internetworks Cisco has taken a completely different approach--one that is simpler and works with all of its networking devices. Where 3Com and Bay sent us many different switches with software for each that overlapped in functionality, Cisco sent one switch type and a point product suite. Cisco Works is a rock-solid product, and it does not rely on a third-party management platform like HP OpenView. No Messin' Around Cisco Works is comprised of Cisco View, Cisco Traffic Director, VLAN Director and other applications. Although each of the three main applications runs separately, it makes the most sense to start with VLAN Director. As the name suggests, this is Cisco's VLAN management application, and it is central to the company's switch management approach. VLAN Director uses a file manager metaphor to list VLANs hierarchically. Cisco refers to these arrangements as management doma ins. These domains are assigned using the VLAN Trunk Protocol (VTP), Cisco's proprietary trunking protocol. This means an extra command-line interface (CLI) step and some planning is necessary if the network is going to be segregated into separate domains. We tested Traffic Director with two domains at our Syracuse University lab, which w as build around a Catalyst 5000 switch. The maps created by Cisco provided a good global look at the switches--by domains and by VLANs--with another graphical fanout showing the switch port(s) by VLAN membership. Cisco does only port-level VLANs, making this application very simple and straightforward when compared with network-layer VLANs. Cisco Works also eliminates the complexity that network-layer VLANs introduce to the troubleshooting process. We found the view Cisco provides difficult to read as the VLANs ranged over multiple switches. An alignment of the VLANs by switch, or Domain Name Service (DNS) resolution--or better yet, a sortable tabular display, like that found in 3Com's Status View application--would have been better. Cisco is aware of the problem and said it would address it in its next release. Give It All to Me Each switch's bitmapped device view was launchable from the VLAN Director and maintained links between it and Cisco View. CLI functions were available from the Cisco View application, as were the expected graphs and charts on performance and load. We were able to drag and drop ports from this device view into the VLAN Director to create VLAN assignments. Additionally, we could highlight the corresponding ports on the device view via the color-coding scheme.

Updated May 12, 1997