01-28-2016 11:07 AM - edited 03-05-2019 03:13 AM
I have a question I need an answer on, so hopefully someone has done this in production. We have a trunk coming from a cloud provider, they assign a /31 block, 255.255.255.254 IP for the links. I am labbing this up on 2811 routers and discovered when I use a /31 I cannot ping across the link. Since the actual connection will be layer 2 back to our router, through a series of switches, and will terminate on a subinterface, I have the lab setup as it will be in production. If I use a /30, of course it works fine.
What I need to know is if on the ASR 1001-X if a /31 address will work in this scenario, as in platform specific issues, or older IOS issues. I do know that earlier versions in the same train wont even allow me to do a /31 subnet. I basically can't imagine it not working on the newer platform since cloud providers use a trunk to connect to the customer and route various networks over it using /31 subnets.
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01-28-2016 11:42 AM
just verified, this works on IOS XE as well. I have tested it on XE 3.16 release - 15.5(3)S
01-28-2016 11:26 AM
Hello,
i tried it on VIRL and it works fine. I am using 15.5 release. What is the IP address that you are using on both sides?
01-28-2016 11:26 AM
Will check it on IOS XE as well and see if there is any issue noticed
01-28-2016 11:42 AM
just verified, this works on IOS XE as well. I have tested it on XE 3.16 release - 15.5(3)S
01-28-2016 12:20 PM
Perfect, that is what I needed to know. I am running older 12.4 code on a pair of 2811, and had a feeling it was just due to the IOS version and/or platform. For an IP I use 66.77.88.1 and just realized WHY it didn't work. DOH, OK back to subnetting school for me. I will try with the CORRECT IP addresses of 0 and 1.
EDIT. Yeah, thats what it was. I put the correct IP's on the interface so they fall into the proper subnet and bingo, got it working, along with VRF and BGP import/export routing. Now just need to get BGP into OSPF and vise versa for internal routing and then my POC will be done.
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