# GATE2005-26

2.9k views

In a network of LANs connected by bridges, packets are sent from one LAN to another through intermediate bridges. Since more than one path may exist between two LANs, packets may have to be routed through multiple bridges. Why is the spanning tree algorithm used for bridge-routing?

1. For shortest path routing between LANs

2. For avoiding loops in the routing paths

3. For fault tolerance

4. For minimizing collisions

Since, in a spanning tree, there is a unique path from a source to the destination, which avoids loops, since it is a tree, and contains all the nodes, since it is a spanning tree.

edited by
1
is A wrong?
6
I guess the MST uses the shortest path to build the tree without forming the loop in the tree. Option A only deals with shortest path routing, which is i guess not appropriate as compared with option B which is more clear according to MST. If the option A was "For avoiding loops in the routing table using the shortest path" then this would have made somewhat sense

Option (b)

0
is this in syllabus of GATE18?
0
@Skyby token ring and bridges are removed
0

@ but this comes under routing

For avoiding loop we use spanning tree algorithm.
ans is b

## Related questions

1
6.6k views
Consider a simple graph with unit edge costs. Each node in the graph represents a router. Each node maintains a routing table indicating the next hop router to be used to relay a packet to its destination and the cost of the path to the destination through that router. Initially, the routing table is empty. ... to node $A$ at time $(t + 100)$ is : $>100$ but finite $\infty$ $3$ $>3$ and $\leq 100$
An IP router implementing Classless Inter-domain Routing (CIDR) receives a packet with address $131.23.151.76$ ... The identifier of the output interface on which this packet will be forwarded is ______.