07-19-2023 09:36 AM
what is loading ,route tag ,reliability,TAG in below---
AAA#sh ip route x.x.x.x
Routing entry for x.x.x.x/25
Known via "eigrp 100", distance 170, metric 2688256
Tag 65207, type external
Redistributing via eigrp 100
Last update from XXXXXXX on TunnelXXXXXX, 05:21:32 ago
Routing Descriptor Blocks:
X.X.X.X, from XXXXXX, 05:21:32 ago, via TunnelXXXXXX
Route metric is 2688256, traffic share count is 1
Total delay is 100010 microseconds, minimum bandwidth is 20000 Kbit
Reliability 255/255, minimum MTU 1472 bytes
Loading 3/255, Hops 2
Route tag 65207
* X.X.X.X, from X.X.X.X, 05:21:32 ago, via TunnelX.X.X.X
Route metric is 2688256, traffic share count is 1
Total delay is 100010 microseconds, minimum bandwidth is 20000 Kbit
Reliability 255/255, minimum MTU 1472 bytes
Loading 3/255, Hops 2
Route tag 65207
07-19-2023 09:43 AM - edited 07-19-2023 09:52 AM
Hello @knaik99,
In the context of routing, "Loading" refers to the current level of network traffic load or congestion on the route to the destination. It is usually represented as a value between 0 and 255, with 255 indicating the highest level of loading or congestion. A lower value suggests a less congested route. This information is used by routing protocols to make better decisions about path selection, preferring less congested routes when possible. The term "loading" is commonly found in routing protocols like EIGRP and is part of the metric calculation, but it doesn't refer exclusively to EIGRP. In the output you provided, "loading 3/255" indicates the current loading level, where 3 is the numerator (current loading) and 255 is the denominator (maximum loading). A lower loading value generally suggests a less congested route.
The "Route tag" is a value used to identify a specific route or set of routes within a routing table. Route tags are often used for administrative purposes, to mark routes with specific attributes or to filter routes when redistributing them between different routing protocols. In the given output, the route is tagged with the value "65207," which could have some administrative significance within the network.
The "Reliability" value indicates the stability and reliability of a route. It is often represented as a fraction, where the numerator represents the current reliability, and the denominator represents the best possible reliability (both values ranging from 0 to 255). In this example, the reliability is shown as "255/255," which means the route is considered completely reliable.
In this given context, "TAG" stands for "Type Attribute Group." The presence of "Tag 65207, type external" in the routing entry indicates that the route is an external route. In the context of EIGRP, external routes are learned from another AS and are redistributed into the local AS.
07-19-2023 09:47 AM
Since you run eigrp then all these value is need to calculte metric
Load and reliability and BW.
For tag this route redistrubte and when it redistrubte tag add to route (this tag transfer via eigrp).
Why we need tag to to some prefix filter.
07-19-2023 10:23 AM
Yeah what @MHM Cisco World in this context its the metrics EIGRP uses to determine a best path. By default it will use the links cumulative delay and lowest BW in the path.
The 1 indicates its being included in the metric and the 0 indicates its Zero'ed out. You can modify the metrics to include the other values but its not really recommended. If you do then all devices in the same domain need to have it configured the same.
-David
07-20-2023 08:09 AM
Hello @knaik99 ,
the route is originated by redistribution into EIGRP domain made on another router
>> Tag 65207, type external
the route tag 65207 is a 32 bit integer attribute associated to the route during redistribution , it can be automatically set to AS number of BGP if redistributing from BGP on that other node or it can have been seen set manually using a route-map in the redistributing router.
All the other values are actually the components of the seed metric used to create the EIGRP composite metric during redistribution.
By default only cumulative delay in tens of microseconds and the inverse of lowest bandwidth in the path in Kbps are used to calculate the composite EIGRP metric.
256 * ( Cumulative_delay + 10^7/minBW)
The values that you see for load and reliability are formal values used in the redistributing router to assign a metric to the external route injected.
They could have been different values and the seed metric would not change because the default K values for them are 0.
The redistributing router that is 2 hops upstream has set the load and reliability values with the seed metric that needs to be configured manually for redistribution from dynamic routing protocols like BGP.
Reliability 255/255, minimum MTU 1472 bytes
Loading 3/255, Hops 2
Route tag 65207
Hope to help
Giuseppe
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