track ip route metric threshold

From: Toh Soon, Lim (tohsoon28@gmail.com)
Date: Fri Aug 17 2007 - 17:49:19 ART


Hi All,

Is anyone familiar with the command "track ip route metric threshold"? I
have the following command to track the metric changes of the OSPF-learned
route 172.30.12.0/26:

track 2 ip route 172.30.12.0 255.255.255.192 metric threshold

R5#sh ip ro 172.30.12.0
Routing entry for 172.30.12.0/26
  Known via "ospf 1", distance 110, metric 782, type inter area
  Redistributing via eigrp 1
  Advertised by eigrp 1 match internal external 1 & 2 route-map O2E
  Last update from 172.30.100.2 on Serial0/0/0, 1d06h ago
  Routing Descriptor Blocks:
  * 172.30.100.2, from 192.168.2.2, 1d06h ago, via Serial0/0/0
      Route metric is 782, traffic share count is 1

R5#sh track 2
Track 2
  IP route 172.30.12.0 255.255.255.192 metric threshold
  Metric threshold is Down (OSPF/782/255)
    1 change, last change 05:55:49
  Metric threshold down 255 up 254
  First-hop interface is Serial0/0/0
  Tracked by:
    VRRP FastEthernet0/0 1

From DocCD, to provide a common interface to tracking clients, route metric
values are normalized to the range of 0 to 255, where 0 is connected and 255
is inaccessible. The resulting value is compared against threshold values to
determine the tracking state. The tracking process uses a per-protocol
configurable resolution value to convert the real metric to the scaled
metric.

I know the metric resolution has to do with the conversion and OSPF default
value is 1 from the output of "show track resolution".

R5#sh track resolution
Route type Metric Resolution
static 10
EIGRP 2560
OSPF 1
ISIS 10

From my output, what is exactly the scaled metric of that OSPF route with
real metric of 782? How is the metric being normalized to the scale of 0-255
using the metric resolution parameter? The track state shows Down, i.e. the
scaled metric for that route must be >= to the down threshold (default 255).

Kindly help me understand.

Thank you.

B.Rgds,
Lim TS



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