Abstract

3Com Corporation commissioned The Tolly Group to benchmark the effectiveness of its DynamicAccess Traffic Prioritization for the TokenLink Velocity ISA adapter. The feature allows network managers to prioritize IP or IPX traffic from selected Token Ring stations. This assures consistent throughput levels even in congested environments. 

Using NT 4.0 systems, The Tolly Group conducted “before” and “after” testing to determine the effectiveness of 3Com’s prioritization scheme. 3Com’s Token- Link Velocity ISA adapter was tested along with Madge Networks’ Presto PCI adapter in a single LAN environment. (The Presto PCI product represented non-3Com adapters.) Additionally, the 3Com TokenLink Velocity ISA adapter was benchmarked across a LAN switch. Testing was conducted in July and Au- gust of 1997. 

Test results show that the 3Com TokenLink Velocity ISA with DynamicAccess Traffic Prioritization guarantees band- width for mission critical applications running on a Token Ring LAN, even if the network is heavily loaded. For tests run on a single 16 Mbit/s Token Ring LAN, the 3Com TokenLink Velocity ISA with Traffic Prioritization delivered bandwidth that varied no more than 10% (IP Batch 2,048-byte test). This contrasts with the TokenLink Velocity ISA with Traffic Prioritization disabled, which de- livered throughput that varied up to 44% during an IP Interactive 1,024-byte test. 

The Madge Presto PCI adapter delivered throughput that varied up to 58% during the IP Batch 1,024-byte test. See figure 4 for complete tabular results for the single 16 Mbit/s LAN tests.