Abstract

Tolly Group Report #202155 (November 2002) compares the Enterasys XSR-1850 Security Router with Cisco’s 2651XM Multiservice Router in a LAN-to-LAN setup stressing three conditions: baseline Layer-3 forwarding, Quality of Service (QoS) inspection, and Access-Control List (ACL) filtering. Tests required zero-loss delivery (≤0.001% packet loss) across full-duplex Fast-Ethernet links while sweeping packet sizes from 64 to 1,518 bytes.

Baseline throughput. In plain Layer-3 forwarding the XSR-1850 pushed 96% of line rate at 512-byte packets and larger, while the Cisco 2651XM managed only 27–31% under the same conditions. Packet-per-second figures mirrored the gap: Enterasys sustained 46,554 pps with 64-byte frames versus Cisco’s 35,360 pps, and 16,223 pps with 1,518-byte frames versus Cisco’s 4,976 pps.

Impact of security features. With QoS enabled the XSR-1850 still hit 100% of line rate at 1,518 bytes and 74% at 512 bytes, whereas the 2651XM dropped to 30% in both cases. Applying 20 bidirectional ACL rules saw Enterasys forward 100% at 1,518 bytes and 63% at 512 bytes, compared with Cisco’s 30% and 29% respectively.

Overall, the XSR-1850 consistently delivered three-times—or more—the zero-loss throughput of the Cisco 2651XM across most packet sizes, even when QoS or ACL processing was active, thanks to hardware acceleration and higher per-packet processing capacity. For branch offices that need high bandwidth with active policy enforcement, the XSR-1850 provides the performance headroom Cisco’s router cannot.