Network connectivity: A response to RFC 603 (RFC0613)
Original Publication Date: 1974-Jan-01
Included in the Prior Art Database: 2019-Feb-12
Internet Society Requests For Comment (RFCs)
Network Working Group Alex McKenzie RFC # 613 BBN-NET NIC # 21525 January 21, 1974
Network connectivity: A response to RFC #603
Network topology is a complicated political and economic question with obvious technical overtones. I shall not attempt, in this note, to cover all the possible arguments which might be made, but merely to respond directly to the points raised in RFC #603.
1. The important consideration in deciding whether it is good or bad to have a node (AMES) be four connected is not how many circuits are affected by a node failure; rather one should consider how well the network is still connected after a node failure. For example, if ALL nodes in the network were four-connected I doubt that anyone would argue that this was bad for reliability. The weaknesses are not the three-connected and four-connected nodes but rather the ONE-connected (Hawaii, London) and two-connected nodes. I must agree with Burchfiel’s implied argument that it is better to have two adjacent three-connected nodes than to have a four-connected node adjacent to a two-connected node; unfortunately the realities of installing interfaces and common carrier services cause the Network to expand in sub-optimal ways.
2. "Loops" are not good per se, they appear good because the act of making loops increases the connectivity and thereby reduces the effect of multiple failures. Adding more circuits costs ARPA money, both capital cost for IMP interfaces and recurring cost for the circuits. The network...