ibgp next-hop-self vs. advertising external links

What are the pros and cons of using next-hop-self or advertising the external links:

This is what comes tomy mind, but I'm curious what service provider guys think.

​

Advertising the external link into the IGP:

-feels a bit more natural. you just add one more route advertisement to the network, rather than altering the default behavior of bgp.

-If the external link fails, the border router will withdraw the external routes in both cases. But if the external link is advertised (rather than the next-hop-self command being used), the failure of the link will cause the IGP to withdraw the external next hop, thus the other IBGP routers will also find out through the IGP that something is wrong, and stop using those routes. The IGP is likely to be faster than iBGP, especially when a route reflector is in use. The IGP also only has to withdraw one route versus the potentially hundreds of thousands that iBGP would have to , thus bringing everything down very quickly and allowing for a faster failover.

​

Using next-hop-self command:

- You don't advertise the external links, thus you don't expose that network to any external attacks. At an Internet Exchange, that might be a shared network, and you would not only expose yourself, but also others. It may be that in such a setup the IX would require that you use next-hop-self, but what do I know?

-You get to choose the next hop addresses. Since these will be very important in your network design, you should take care when you design the network that these are easy to remember. This will make it much easier to read BGP tables, if you know the next hops, whereas if there are multiple peers, you are unlikely to remember the link addresses used to peer with them.