Routing Protocols Flashcards
RIP
Routing Information Protocol
IGP
-will consider only one route to a given destination network
distance-vector using hop count
max hops = 15
Runs over udp
-oldest dynamic routing protocol
-provided updates every 30 seconds
-ripv1 does not support vlsm
OSPF
Open Shortest Path First
IGP
Link state using cost
Classless
Developed for IP networks and based on SPF algorithm.
Suited to large organizations with multiple redundant paths between networks.
High convergence
IS-IS
Intermediate System to Intermediate System
IGP
Link state using cost
Functions like OSPF, not as popular
Classless
EIGRP
Enhanced Interior Gateway Routing Protocol
IGP
Hybrid - advance distance vector using bandwidth and delay
Proprietary Cisco protocol
Classless
Uses metric composed of several admin weighted elements such as “bandwidth” and “delay”
Distance vector-based routing protocol and uses a metric composed of several admin weighted elements (reliability, bandwidth, load)
BGP
Border Gateway Protocol
EGP
Path vector using autonomous system hops instead of router hops
Backbone of internet
Does not converge quickly
Between routing domains
Primarily between ISPs
IGP
Internal Routing Protocol
Within autonomous system
EGP
External Routing Protocol
Between autonomous system
Distance Vector
-Router Advertisement Method
-Sends full copies of routing tables to directly connected neighbors
-Slow convergence time
-hop count
-holding-down timers speeds up convergence (prevents updates for specific time)
-a routing algorithm
Link State
Routing Advertisement Method
-interface monitoring metric. Measures if interface is working or not.
-stores complete network topology and assesses the least-cost paths from this database
-Fastest way, uses cost as metric
-faster convergence time
-Each router constructs it’s own shortest-path tree with itself as root
-requires all routers know about the paths that all other routers can reach in the network
-information flooded throughout link-state domain(OSPF and is-is) to ensure routers have synchronized info
Route believability
Directly connected - 0
Statically configured network - 1
EIGRP - 90
OSPF - 110
RIP - 120
External EIGRP - 170
Unknown - 255(unreachable)
Routing metrics
Hop count
Bandwidth
Reliability
Believability
Delay
Etc.
Classless protocol meaning
Routers include subnet mask information when routing tables are exchanged.
Split Horizon
Prevents routing loops by preventing a route learned on one interface from being advertised back out that same interface.
Poison reverse
Prevents routing loops
-causes a route received on one interface to be advertised back out of that same interface with a metric considered to be infinite
NAT (network address translation)
-translates private ip to public ip
-inside local(private ip of inside device)
-inside global(public ip inside device)
-outside local(priv ip outside device)
-outside global(priv ip outside device)
-DNAT(dynamic nat)
—one-to-one transactions
—address assigned from pool
-SNAT(static nat)
—one-to-one transactions
—ip manually assigned
-PAT(post address translation)
—many-to-one transactions
—multiple private IPs share 1 public
—uses port numbers instead of IPs
