So, what is “connectivity” ?
Direct or indirect “access” to every other node in the network
Access is not the same as having a pt-pt link
- What you get is a “virtual channel” between nodes, which does not necessarily have the same performance characteristics of a physical link.
- For example, a virtual channel may minimally provide only “best-effort connectivity on a packet-by-packet basis” whereas a link provides an "always-connected, fixed bandwidth, fixed delay and near zero-jitter" channel.
Just connectivity may not be enough for some applications. They might need more services to make the channel look meaningful to them...