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← Revision 12 as of 2004-03-17 21:32:02 ⇥
Size: 1803
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| Deletions are marked like this. | Additions are marked like this. |
| Line 1: | Line 1: |
| Back to ComputerTerms |
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| Line 4: | Line 6: |
| * What: Send Link stata packet about dirrect connected links | * What: Send Link state packet (LSP) about direct connected links |
| Line 6: | Line 8: |
| * How: Reliable flooding | |
| Line 7: | Line 10: |
| Local information globally | The point is that Local information is distributed globally. |
| Line 9: | Line 12: |
| Uses OpenShortestPathFirst OSPF algorithm | The LSP information recieved is used to create a graph of the network. Then routing is easy because we use DijkstrasAlgorithm, to find the shortest path. See cse952lec03.pdf. The LSP contains the following information 1. ID of the node that created the LSP 2. List of directly connected neighbors, cost of link 3. A sequence number 4. TTL OpenShortestPathFirst OSPF is an example protocol Given a network that looks like {{{ 2 A---------C |\ / \ | \5 /2 \1 | \ / \ 3| D F | / \ / | /1 \3 /2 |/ \ / B---------E 4 }}} Dijkstra's Algorithm goes through the following steps: ||Step||||Confirmed||||Tentative|| ||1 ||||(A,0,-) ||||(C,2,C),(B,3,B),(D,5,D)|| ||2 ||||(A,0,-),(C,2,C) ||||(B,3,B),(D,4,C),(F,3,C) || ||3 ||||(A,0,-),(C,2,C),(B,3,B) ||||(D,4,C),(F,3,C),(E,7,B)|| ||4 ||||(A,0,-),(C,2,C),(B,3,B),(F,3,C) ||||(D,4,C),(E,5,C)|| ||5 ||||(A,0,-),(C,2,C),(B,3,B),(F,3,C),(D,4,C) ||||(E,5,C)|| ||6 ||||(A,0,-),(C,2,C),(B,3,B),(F,3,C),(D,4,C),(E,5,C) ||||None || This produces the following routing tables ||Destination||||Next Hop||||Cost|| ||A||||-||||0|| ||C||||C||||2|| ||B||||B||||3|| ||F||||C||||3|| ||D||||C||||4|| ||E||||C||||5|| Alternately we could have just written line 6. === Plus === * LinkState is fast statble and takes a log of space. * It is founded upon reliable flooding. Back to ComputerTerms |
Back to ComputerTerms
Link State Protocol
- Who: Send to all nodes
- What: Send Link state packet (LSP) about direct connected links
- When: Periodically or when a change occurs (triggered)
- How: Reliable flooding
The point is that Local information is distributed globally.
The LSP information recieved is used to create a graph of the network. Then routing is easy because we use DijkstrasAlgorithm, to find the shortest path. See cse952lec03.pdf. The LSP contains the following information
- ID of the node that created the LSP
- List of directly connected neighbors, cost of link
- A sequence number
- TTL
OpenShortestPathFirst OSPF is an example protocol
Given a network that looks like
2
A---------C
|\ / \
| \5 /2 \1
| \ / \
3| D F
| / \ /
| /1 \3 /2
|/ \ /
B---------E
4Dijkstra's Algorithm goes through the following steps:
Step |
Confirmed |
Tentative |
||
1 |
(A,0,-) |
(C,2,C),(B,3,B),(D,5,D) |
||
2 |
(A,0,-),(C,2,C) |
(B,3,B),(D,4,C),(F,3,C) |
||
3 |
(A,0,-),(C,2,C),(B,3,B) |
(D,4,C),(F,3,C),(E,7,B) |
||
4 |
(A,0,-),(C,2,C),(B,3,B),(F,3,C) |
(D,4,C),(E,5,C) |
||
5 |
(A,0,-),(C,2,C),(B,3,B),(F,3,C),(D,4,C) |
(E,5,C) |
||
6 |
(A,0,-),(C,2,C),(B,3,B),(F,3,C),(D,4,C),(E,5,C) |
None |
||
This produces the following routing tables
Destination |
Next Hop |
Cost |
||
A |
- |
0 |
||
C |
C |
2 |
||
B |
B |
3 |
||
F |
C |
3 |
||
D |
C |
4 |
||
E |
C |
5 |
||
Alternately we could have just written line 6.
Plus
LinkState is fast statble and takes a log of space.
- It is founded upon reliable flooding.
Back to ComputerTerms