NameCheap-Hosting

استفد من الخصومات على خدمات الاستضافة بمختلف انواعها

VPS hosting: up to 30% off!

الجمعة، 10 يونيو 2011

Routing Protocols Comparison


RIP v1
RIP v2
EIGRP
OSPF
BGP
Interior/Exterior?
Interior
Interior
Interior
Interior
Exterior
Type
Distance Vector
Distance Vector
Hybrid distance vector
Link-state
Path Vector
Default Metric
Hop count
Hop count
Delay, bandwidth, reliability, and load, using the Diffusing Update Algorithm (DUAL)
Cost
Multiple Attributes
Administrative Distance
120
120
90 (internal)
170 (external)
110
20 (external)
200 (internal)
Hop count Limit
15
15
224 (100 default)
None
EBGP Neighbors: 1 (default)
IBGP Neighbors: None
Convergence
Slow
Slow
Very Fast
Fast
Average
Update timers
30 seconds
30 seconds
Only when change occurs
Only when changes occur;
(LSA table is refreshed every 30
minutes, however)
Only when changes occur
Updates
Full table
Full table
Only Changes
Only Changes
Only Changes
Classless
No
Yes
Yes
Yes
Yes
Supports VLSM
No
Yes
Yes
Yes
Yes
Algorithm
Bellman-Ford
Bellman-Ford
DUAL
Dijkstra
Best Path Algorithm
Update Address
Broadcast
224.0.0.9
224.0.0.10
224.0.0.5 (All SPF Routers)
224.0.0.6 (DR’s and BDR’s)
Unicast
Protocol and Port
UDP port 520

IP Protocol 88
IP Protocol 89
TCP port 179
Methodology
Selects routers with the lowest hop count
Selects routers with the lowest hop count
Sends hello packets every five seconds to neighbors (can interoperate with IGRP) to see if the neighbors are still available
Develops adjacencies with its neighbors, periodically sending hello packets to neighbors, flooding changes to neighbors when a link’s status changes, and sending “paranoia updates” to neighbors every 30 minutes of all recent link state changes
If the network, its complete AS path, and the gateway are correct,
   Then the route is compared with other routes to the same network.  If
   the new route is better than the current one, then it is flooded to
   other BGP peers

Ideal topology
Smaller networks that aren’t very dynamic, have fewer than 15 hops, and are not subnetted from classful boundaries
maller networks that aren’t very dynamic, have fewer than 15 hops
Any network, small to very large; all routers must be Cisco
Any network, small to very large
Used by ISPs & Large Enterprises.
Standard
proprietary of Cisco
RFC 1105
Strengths
- Easy to configure and use.
- Since it has been around so long, it is well known and widely used.

- Easy to configure and use.
- Since it has also been around so long, it is well known and widely used.
- Version 2 adds support for VSLM or Classless Internet Domain Routing (CIDR), MD5 Authentication, and route summarization.

- Uses DUAL to provide very quick convergence and a loop-free network.
- Supports IP and IPX.
- Requires less CPU than OSPF (see next section).
- Requires little bandwidth for routing updates.
- Supports VLSM or CIDR.
- Uses the delay, bandwidth, reliability, and load of a link as its metric; this makes it very accurate in selecting the proper route.
- Offers backward compatibility with IGRP.

- Converges quickly, compared to a distance vector protocol.
- Routing update packets are small, as the entire routing table is not sent.
- Not prone to routing loops.
- Scales very well to large networks.
- Recognizes the bandwidth of a link, taking this into account in link selection.
- Supports VLSM or CIDR.
- Supports a long list of optional features that many of the other protocols do not.


Weaknesses
- Limited to a hop count of 15; after a packet travels through 15 routers and still has another router to travel to, it will be discarded.
-Doesn’t support a variable-length subnet mask (VLSM), which means that it sends routing updates based only on a fixed-length subnet mask (FLSM) or routes that fall on classful boundaries. So RIP V1 will not work with a network that has been subnetted beyond the normal /8, /16, /24 (255.0.0.0, 255.255.0.0, 255.255.255.0) or Class A, B, and C network boundaries.
-Converges slowly, especially on large networks.
- Doesn’t have knowledge of the bandwidth of a link.
- Doesn’t support multiple paths for the same route.
- Routing updates can require significant bandwidth, as the entire routing table is sent when a link’s status changes.
- Prone to routing loops.
- Limited to a hop count of 15; after a packet travels through 15 routers and still has another router to travel to, it will be discarded.
- Converges slowly, especially on large networks.
- Doesn’t have knowledge of the bandwidth of a link.
- Doesn’t support multiple paths for the same route.
- Routing updates can require significant bandwidth as the entire routing table is sent when a link’s status changes.
- Prone to routing loops.

- Not an Internet standard; all routers must be from Cisco Systems.
More complex to configure and understand than a distance vector protocol