RE: A question on CE to PE route exchanges ...
Oops... I answered this privately, assuming NANOG at large would not be interested. The issue here is that Cisco will tend to add IGP routes to the default table, not the VPN table. Bad things ensue. I was actually referring to the CE interface address; peering with the CE's loopback is, IMHO, more trouble than its worth unless you have multiple connections on the same router. But as long as the address you are peering with is in the private routing table, you're fine, regardless of whether or not it is also in the default table. I cannot speak to the "most common;" I think it is too early to tell. But we are tending towards static routes (nice and stable, without the chance of the other guy breaking you) and BGP (which is already designed to handle trans-border communication.) I have not tried it, but I would assume the OSPF area "repair" toys would work nicely over this, if you want an IGP running across your CE routers. (I'm more of an ISIS guy than an OSPF guy... anybody know why this would blow up in your face?) -Dave On 5/19/2001 at 21:14:40 -0700, Elwin Eliazer said:
Even i am interested in knowing the exact issue with using IGPs? What is the most common CE-PE route exchange behaviour now ... Static routes OR IGP OR BGP??
Dave, are you referring the CE loopback address also to be local?
cheers, Elwin.
--- Alex Mondrus <alex.mondrus@ipoptical.com> wrote:
Dave
I also like the RFC2547bis.
I would like to learn more about your painful experience with IGP in this context. Please elaborate a little bit more on this subject -> Dave Israel wrote "Besides, in at least one major current implementation, your IGP options are painfully limited."
Thanks in advance, Alex
-----Original Message----- From: Dave Israel [mailto:davei@biohazard.demon.digex.net] Sent: Friday, May 18, 2001 5:45 PM To: Elwin Eliazer Cc: nanog@merit.edu Subject: Re: A question on CE to PE route exchanges ...
On 5/18/2001 at 14:13:53 -0700, Elwin Eliazer said:
Hi,
RFC2547bis suggests the use of EBGP between CE and PE routers; Is this a preferable model for service providers and enterprise customers, when compared to using IGP?
Yes. BGP is designed for network borders. Besides, in at least one major current implementation, your IGP options are painfully limited.
Are there anyone who have deployed this? If so, how is the EBGP peering setup if the CE router is with a local (VPN) IP address?
The BGP session lives in VPN space, the routes only exist in VPN routing tables. Your CE having a VPN address is really just the natural solution.
-Dave
===== ------- Elwin Stelzer Eliazer Corona Networks -------
__________________________________________________ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/
-- Dave Israel Senior Manager, IP Backbone Intermedia Business Internet
not be interested. The issue here is that Cisco will tend to add IGP routes to the default table, not the VPN table. Bad things ensue.
What ... ? For protocols that have been vrf aware routes go into vrfs and not global RIB. Those IGPs would be in shipping images: RIP, OSPF. Very soon also EIGRP & ISIS. Just watch your CPU before using IGPs on a wide scale with tons of customer routes flappoing :). Just not be understood that I recommend the above IGPs :) I am also seeing worldwide the following set of protocols on the PE-CE in order or preference: static, BGP & RIP. R.
Dave Israel wrote:
Oops... I answered this privately, assuming NANOG at large would not be interested. The issue here is that Cisco will tend to add IGP routes to the default table, not the VPN table. Bad things ensue.
I was actually referring to the CE interface address; peering with the CE's loopback is, IMHO, more trouble than its worth unless you have multiple connections on the same router. But as long as the address you are peering with is in the private routing table, you're fine, regardless of whether or not it is also in the default table.
I cannot speak to the "most common;" I think it is too early to tell. But we are tending towards static routes (nice and stable, without the chance of the other guy breaking you) and BGP (which is already designed to handle trans-border communication.)
I have not tried it, but I would assume the OSPF area "repair" toys would work nicely over this, if you want an IGP running across your CE routers. (I'm more of an ISIS guy than an OSPF guy... anybody know why this would blow up in your face?)
-Dave
On 5/19/2001 at 21:14:40 -0700, Elwin Eliazer said:
Even i am interested in knowing the exact issue with using IGPs? What is the most common CE-PE route exchange behaviour now ... Static routes OR IGP OR BGP??
Dave, are you referring the CE loopback address also to be local?
cheers, Elwin.
--- Alex Mondrus <alex.mondrus@ipoptical.com> wrote:
Dave
I also like the RFC2547bis.
I would like to learn more about your painful experience with IGP in this context. Please elaborate a little bit more on this subject -> Dave Israel wrote "Besides, in at least one major current implementation, your IGP options are painfully limited."
Thanks in advance, Alex
-----Original Message----- From: Dave Israel [mailto:davei@biohazard.demon.digex.net] Sent: Friday, May 18, 2001 5:45 PM To: Elwin Eliazer Cc: nanog@merit.edu Subject: Re: A question on CE to PE route exchanges ...
On 5/18/2001 at 14:13:53 -0700, Elwin Eliazer said:
Hi,
RFC2547bis suggests the use of EBGP between CE and PE routers; Is this a preferable model for service providers and enterprise customers, when compared to using IGP?
Yes. BGP is designed for network borders. Besides, in at least one major current implementation, your IGP options are painfully limited.
Are there anyone who have deployed this? If so, how is the EBGP peering setup if the CE router is with a local (VPN) IP address?
The BGP session lives in VPN space, the routes only exist in VPN routing tables. Your CE having a VPN address is really just the natural solution.
-Dave
===== ------- Elwin Stelzer Eliazer Corona Networks -------
__________________________________________________ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/
-- Dave Israel Senior Manager, IP Backbone Intermedia Business Internet
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Robert Raszuk