Similarities:
1. The administrator to modify preference are external priority
2. All are dynamic routing protocol, according to the sensing network routing condition

Different:
Ospf
Process only local significance, sunflower structure, suitable for large enterprise environment, faster than rip, static is slower than the eigrp (shortest path first)
Security: three layers of IP
Foundation: 11 class LSA

Rip
Suitable for small area, small company (path vector algorithm)
Mechanism:
Level division: updated routing information from the neighbor, then local won't send neighbor
Toxicity reverse: 16
Every 30 s to the neighbor broadcast the local routing table, receipt of neighbors, for local maintenance, USES the timeout mechanism to ensure that the routing efficiency,
30 s (update) - 180 s (change the hop count to 16) to 120 (delete) routing information

ISIS
Suitable for campus network, operator environment (simpler) structure, flat structure; The ospf has fewer scholars;
Security: MAC level, relative to the ospf safer

BGP
Between autonomous domain (distance vector algorithm)
Foundation: rules, strategy
Ebgp (20 priority) is better than that of ibgp (200).