How long for BGP to propogate PI address worldwide with new ISP?

[Peter_Kavanagh]

Hi,

I started in a new role 2 weeks ago and have inherited a project to migrate over to a new ISP. I'm on a BGP learning curve having never done any real work with it before and looking for some help along the learning curve.

We're a Eurpoean office of a US company who has our own ASN and PI address space (I see it registered on arin.net). One /24 has been allocated to our site (I see a "route:" entry for that /24 on the ripe.net db) and at the moment it's being announced by ISP A but with the ISP's ASN. No one here know the history and the last guys has gone travelling so can ask him why we don't use our own. Not sure if that's legit or not??

We want to move to ISP B, but they want us to use the ASN we own. Fair enough, I thought and we changed over last weekend. All seemed well until our guy in Autralia said he still couldn't reach us after an hour. Google led me to a Looking Glass server out there, and sure enough, no route in the table for our prefix. There were several places worldwide with the same issue and it seems some ISP had our route but some did not, so we backed out. All back to normal on the ISP A within a few minutes.

So my questions:

1) Were we too hasty, and should we have waited it out another hour (or what?) to let the routes propogate? We waited about 70 mins in total which  eems like a long time to me but I'm a virgin here!

2) Is there some issue I have with changing the ASN? Nothing I've read this week has indicated that, but I'm still trying to learn ... in the odd 5 minute widows between doing everything from fixing printers to sync'ing the CEO's iPhone

3) Have I missed something entirely?

I'm appreciate any help, pointers, etc and feel free to correct my terminology if I'm expressing anything incorrectly, as I said I'm new to this area.

Thanks,

Pete.

[Edison Ortiz]

70mins may not be enough if ISP B is not a 'tier 1' provider. A non-tier 1 provider will rely on tier 1 providers for subnet propagation.

As long as you own the ASN, changing it shouldn't be a problem.

[JohnTylerPearce]

Peter,

It sounds like, your ISP (ISPA) "may" have worked out a deal, that they advertise out that PI address space themseleves, then have a static route back to you. I honestly don't know this, but that's what it sounds like. You should be able to call up your ISP and ask them.

The above qustion need to be asnwered first.

Now, when you advertise out your PI address space, I always 'clear the specific BGP session' that needs to be cleared.

This should advertise out the address space from your AS.

Now, were you advertisng this out on an ASN within th 64512-65535 range by any chance? You don't have to post your specific ASN. Also, when you changed over to the new ISP, did your BGP peer session come up successfully?

You can also do commands such as 'show ip bgp neighbor x.x.x.x advertised-routes' and verify that you are advertising the routes to your ISP. From this ISP, you may need to call them up, and verify that are advertising it correctly.

[Peter_Kavanagh]

Thanks for the replies.

We're not using a private ASN., I don't want to publish specifics but it's a 2xxxx number.

I'm not sure what the deal with the old ISP was (is!) but we did have to tell them we were changing over and then rolling back, so that kinda fits what your saying about static routes.

The BGP session came up and we were advertising - it's only a sub set of location that don't work. Some places could traceroute to our firewall after the change.

We've a call in with the new ISP, so I'll see what they say. Hopefully, I was just being impatient/nervous!

[JohnTylerPearce]

Peter,

Thanks for the information. LIke Edison said, it's very possible that 70 minutes is not enough time for all Internet Routers to get the updated information.

Depending on what tier your ISP is, it may take a while to get complete routing connectivity on the Internet to your PI address space.