Packet Design plans to leave no stone unturned - or, more appropriately, no protocol unmonitored.Last year the route analytics company added support for Border Gateway Protocol, and last week it announced that its Route Explorer appliance can now support Cisco\u2019s Enhanced Interior Gateway Routing Protocol (EIGRP).According to Cisco, EIGRP provides compatibility and seamless interoperation with IGRP routers. An automatic-redistribution mechanism allows IGRP routes to be imported into EIGRP, and vice versa. IGRP is a distance-vector interior gateway protocol. Distance-vector routing protocols call for each router to send all or a portion of its routing table in a routing-update message at regular intervals to each of its neighboring routers.Distance-vector protocols differ from link-state protocols such as Open Shortest Path First (OSPF) and IS-IS (Intermediate System-Intermediate System) in that they don\u2019t include network topology information. For example, OSPF and IS-IS include networkwide routing information - on every hop a packet takes among multiple routers.While many Cisco customers run EIGRP on their nets (Packet Design estimates about 60% to 70% in the U.S.), the protocol doesn\u2019t include as much Layer 3, or routing layer, information for network managers to analyze.Packet Design says its upgraded appliance will now show those network managers using EIGRP how routing changes affect network performance. Route Explorer can spot, for example, that a downed link will break the only path to a given prefix because redundant routing is incorrectly configured."Based on hearing the change in distance between router calls, Route Explorer is able to infer what the likely change in the routing is," says Doug Brent, Packet Design CEO.The appliance can be located anywhere on a network - on a switch port or directly adjacent to a router. The appliance can then connect and establish adjacencies to other routers via software tunnels.Route Explorer monitors networkwide EIGRP topology in real time from one appliance, forms routing adjacencies with neighboring routers and gathers information across summarization boundaries. It discovers Layer 3 routing information upon installation, and immediately begins listening to protocol exchanges between routers without adding load to the network, the company says.The EIGRP features also enable network managers to validate root-cause analysis to verify the source of network events and capture router model and IOS version, providing important information on network assets.Pricing for Route Explorer begins at $19,000 and scales to $90,000 or so, based on the size of the network and the type of protocols to be monitored.