# Running Routing Protocols over Tunnels

DevFeed: [Running Routing Protocols over Tunnels](<https://devfeed.tech/articles/running-routing-protocols-over-tunnels-11100.md>)

Original publisher: [Read original article](<https://blog.ipspace.net/2024/11/running-routing-protocols-over-tunnels/>)

Published: 2024-11-05T07:14:00Z

Content type: article

Language: en

Sources: [ipSpace.net blog](<https://devfeed.tech/sources/ipspace-net-blog.md>)

Topics: [networking](<https://devfeed.tech/topics/networking.md>), [Routing (disambiguation)](<https://devfeed.tech/topics/routing.md>), [Protocol (disambiguation)](<https://devfeed.tech/topics/protocol.md>), [BGP](<https://devfeed.tech/topics/bgp.md>), [IS-IS](<https://devfeed.tech/topics/is-is.md>), [MPLS-TE](<https://devfeed.tech/topics/mpls-te.md>), [MPLS VPN](<https://devfeed.tech/topics/mpls-vpn.md>), [evpn](<https://devfeed.tech/topics/evpn.md>), [VXLAN](<https://devfeed.tech/topics/vxlan.md>), [Reason](<https://devfeed.tech/topics/reason.md>)

Tags: [bgp](<https://devfeed.tech/tags/bgp.md>), [evpn](<https://devfeed.tech/tags/evpn.md>), [ip-routing](<https://devfeed.tech/tags/ip-routing.md>), [is-is](<https://devfeed.tech/tags/is-is.md>), [mpls](<https://devfeed.tech/tags/mpls.md>), [mpls-te](<https://devfeed.tech/tags/mpls-te.md>), [ospf](<https://devfeed.tech/tags/ospf.md>), [protocol](<https://devfeed.tech/tags/protocol.md>), [recursion](<https://devfeed.tech/tags/recursion.md>), [routing](<https://devfeed.tech/tags/routing.md>), [vxlan](<https://devfeed.tech/tags/vxlan.md>)

## AI overview

This article explains why routing protocols over tunnels can cause recursive routing and infinite encapsulation. It distinguishes traffic-engineering and IPsec tunnels from VPN designs, where routing protocols exchange customer and transport prefixes using separated address spaces or families.

## Source excerpt

James got confused by a statement made by Hannes Gredler in his IS-IS book: Things behave really badly if the total IGP cost over the tunnel undermines the total topologies' cost. What happens next is that the tunnel "wraps" around itself, ultimately causing a meltdown of the entire network. Let's unpack that, starting with "Why would you need a tunnel?" Read more ...