> So what your telling me that the Cost is the same as the Metric? Cost, is it
>what the link is ( like Ethernet would be a 10? and a 56K circuit would be
>say 1000 ) and a metric would be the cost added upto the destination? or the
best route to take.
The metric varies with the interior routing protocol, but it is
generally the way the router sees the sum of per-interface "values".
BGP does not have a strong concept of metrics.
Protocol AD Per-interface value Metric
-------------------------------------------------------
RIP 120 hop sum of hops
OSPF 100 cost sum of costs
(special costs for inter-area & external)
EIGRP 90 primarily bandwidth & delay
weighting criteria on a weighted composite
per-router basis effectively will
pick path with the
largest bandwidth
minimum on any link
Do remember that "metric" is a tiebreaker for otherwise comparable
routes within the same routing protocol. In hierarchical networks,
the metric may only be useful within a single area, and other
criteria strongly affect the path that will be taken.
In real networks of any size, topology, both physical and area,
usually are far more important than metric. "Best" is something of a
misnomer, because the lowest-metric path isn't always best under some
routing policies. In closest-exit/hot-potato routing, the "best"
path is the one that leaves the area/AS most quickly.
--
"What Problem are you trying to solve?"
***send Cisco questions to the list, so all can benefit -- not
directly to me***
Howard C. Berkowitz [EMAIL PROTECTED]
Technical Director, CertificationZone.com
Senior Product Manager, Carrier Packet Solutions, NortelNetworks (for ID only)
but Cisco stockholder!
"retired" Certified Cisco Systems Instructor (CID) #93005
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