Static to EIGRP Redistribution Metrics

jpl861 · ‎06-20-2018

Hi Experts,

I am trying to understand what happened here. The EIGRP metrics seemed to change after a couple of weeks. Here's a snippet of the configuration.

I tried to generate the summary route from the core for all of the VLANs in 10.226.0.0/16 network. The used route-map to filter the static to EIGRP redistribution so it will be easier for me to set different metrics for different routes. As you can see below, the EIGRP topology used the 40G bandwidth of Null0 with a total delay of 0. Even though this is a static to EIGRP redistribution, the EIGRP process sees it as an internal route and used the Null0 metrics (maybe due to the fact that we used 10.226.0.0/16 as network statement so it treated the summary route as directly connected to Null0).

ip route 10.226.0.0 255.255.0.0 Null0

ip prefix-list CORE-NETS-STATICS permit 10.226.0.0/16

router eigrp 30

network 10.226.0.0 0.0.255.255

redistribute static route-map static_route_filter

6500-VSS#sh route-map static_route_filter

route-map static_route_filter, permit, sequence 100

Match clauses:

ip address prefix-lists: CORE-NETS-STATICS

Set clauses:

metric 1000000 1 255 1 1500

Policy routing matches: 0 packets, 0 bytes

6500-VSS#show int null0 | i BW

MTU 1500 bytes, BW 40000000 Kbit, DLY 0 usec,

6500-VSS#sh ip eigrp topo 10.226.0.0/16

EIGRP-IPv4 Topology Entry for AS(30)/ID(10.226.255.100) for 10.226.0.0/16

State is Passive, Query origin flag is 1, 1 Successor(s), FD is 1

Descriptor Blocks:

0.0.0.0, from Rstatic, Send flag is 0x0

Composite metric is (1/0), route is Internal

Vector metric:

Minimum bandwidth is 40000000 Kbit

Total delay is 0 microseconds

Reliability is 0/255

Load is 0/255

Minimum MTU is 1500

Hop count is 0

Originating router is 10.226.255.100

6500-VSS#sh ip route 10.226.0.0 255.255.0.0

Routing entry for 10.226.0.0/16

Known via "static", distance 1, metric 0 (connected)

Redistributing via eigrp 30

Advertised by eigrp 30 route-map static_route_filter

Routing Descriptor Blocks:

* directly connected, via Null0

Route metric is 0, traffic share count is 1

6500-VSS#

*****************************************************

After a couple of weeks, I noticed that the EIGRP topology metrics changed but the configurations are still the same. It picked the metrics used on the route-map but the route is still internal.

6500-VSS#sh ip eigrp topo 10.226.0.0/16

EIGRP-IPv4 Topology Entry for AS(30)/ID(10.226.255.100) for 10.226.0.0/16

State is Passive, Query origin flag is 1, 1 Successor(s), FD is 1

Descriptor Blocks:

0.0.0.0, from Rstatic, Send flag is 0x0

Composite metric is (2816/0), route is Internal

Vector metric:

Minimum bandwidth is 1000000 Kbit

Total delay is 10 microseconds

Reliability is 255/255

Load is 1/255

Minimum MTU is 1500

Hop count is 0

Originating router is 10.226.255.100

Any idea what's going on here? I have simulated the same thing on the lab and I was able to recreate the same situation (weeks ago) but now it just wouldn't do it in the lab.

Thanks,

John

Georg Pauwen · ‎06-21-2018

Hello,

it looks like the metrics during the redistribution didn't get picked up at first. The output you see after a couple of weeks is what you should have seen right away. I tried your setup in GNS3, and the output I get is this:

Router#sh ip eigrp topology 10.226.0.0/16
EIGRP-IPv4 Topology Entry for AS(1)/ID(10.226.255.100) for 10.226.0.0/16
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 2816
Descriptor Blocks:
0.0.0.0 (GigabitEthernet0/0), from Connected, Send flag is 0x0
Composite metric is (2816/0), route is Internal
Vector metric:
Minimum bandwidth is 1000000 Kbit
Total delay is 10 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 0
Originating router is 10.226.255.100

jpl861 · ‎06-21-2018

Thanks for the reply. I also have a running GNS3 lab right now and it’s using the Null0 metric, not the redistribution metric.

Georg Pauwen · ‎06-21-2018

Hello,

odd. Which IOS are you running ? I am using IOSv15.6(2)T-1...

jpl861 · ‎06-21-2018

I am using 15.4(1)T for IOU. Here’s the testing I am doing on GNS3 but I used 12.0.0.0/8.

The 6500 we are using where I saw this issue is 15.1(2)SY2. It is now using the redistribute metric but for the first couple of weeks it’s using the Null. The 6500 that’s running 12.2(50)SY is using the Null0 metric. And then the other 6500 that’s running 15.1(2)SY4a is using the redistribute metric. All the configs were done around 2 months ago. Weird huh? 😊

IOU2#sh ip route 12.0.0.0 255.0.0.0
Routing entry for 12.0.0.0/8
Known via "static", distance 1, metric 0 (connected)
Redistributing via eigrp 100
Advertised by eigrp 100 route-map STATIC2EIGRP
Routing Descriptor Blocks:
* directly connected, via Null0
Route metric is 0, traffic share count is 1
IOU2#sh ip eigrp topo 12.0.0.0/8
EIGRP-IPv4 Topology Entry for AS(100)/ID(2.2.2.2) for 12.0.0.0/8
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 256
Descriptor Blocks:
0.0.0.0, from Rstatic, Send flag is 0x0
Composite metric is (256/0), route is Internal
Vector metric:
Minimum bandwidth is 10000000 Kbit
Total delay is 0 microseconds
Reliability is 0/255
Load is 0/255
Minimum MTU is 1500
Hop count is 0
Originating router is 2.2.2.2
IOU2#sh inter Null0 | i DLY
MTU 1500 bytes, BW 10000000 Kbit/sec, DLY 0 usec,
IOU2#sh route-map
route-map STATIC2EIGRP, permit, sequence 100
Match clauses:
Set clauses:
metric 32 1 255 1 1500
Policy routing matches: 0 packets, 0 bytes
IOU2#sh run | sec router eigrp
router eigrp 100
network 12.0.0.0
redistribute static route-map STATIC2EIGRP
IOU2#