Hi, I have been reading through the documentation at BGP Multihop Sessions - TechLibrary - Juniper Networks and trying to understand how this best relates to my needs.
At present I have a simple EGBP configuration that does a failover default route between two ISP's and brings in routes from INET 2. All go through directly connected peers and I haven't had a need to do a loopback address. We export 1 class C range with our AS. I keep this as simple as possible because we don't have any Juniper experts.
But we needed to add in Comcast Xfinity streaming routes that require a multi hop peer along with a normal neighbor and I am not sure of the best way to do this.
Key questions:
1. The documentation is using different logical sessions which I don't think I need. Is this correct? These routes should be additions to our routing table but not a separate process.
2. Can I add a loopback for the multihop address without needing to do the same for all peers?
3. Can I configure this under the current external peers group or do I need to add a new group for multihop specific configurations?
4. Any other pitfalls and issues I should be aware of?
This is bgp parts of the config as is before changing anything.
Comcast gave me a cisco example.
!Physical CPE port
Interface gige x/x
Description Connection to Comcast CPE
No ip address
No shut
!Logical interface used to connect with CPE
interface gige x/x.<vlan-id>
description Connection to Comcast network
encap dot1Q <vlan-id>
ip address <other side of /30> 255.255.255.252
mtu 1500
< Add other interface parameters as needed>
!Static route needed for FULL-ROUTE customer to build MH-BGP session with Ibone PE ***
ip route <ip address of PE loopback1(Comcast to provide)> 255.255.255.255 <interface.<vlan-id>> <SUR interface ip address(Comcast to provide)>
!Used to aggregate prefixes to advertise via BGP
ip route <ip address agg> /<mask> null0
! Used to limit routes announced to SUR
ip prefix-list PERMIT-TO-COMCAST seq 5 permit <agg to announce>
!Used to NOT announce anything to the 2nd BGP session.
ip prefix-list DENY-TO-COMCAST seq 5 deny 0.0.0.0/0
!Primary bgp session with SUR
router bgp <customer ASN>
no synchronization
bgp router-id <loopback0>
network <ip address agg/mask>
neighbor <SUR interface ip address> description Peering Session with Comcast
neighbor <SUR interface ip address> remote-as 7922
neighbor <SUR interface ip address> send-community
neighbor <SUR interface ip address> prefix-list PERMIT-TO-COMCAST out
!Second FULL-ROUTE customer session
neighbor <PE Loopback ip address> description Peering Session with Comcast
neighbor <PE Loopback ip address> remote-as 7922
neighbor <PE Loopback ip address> ebgp-multihop 255
neighbor <PE Loopback ip address> send-community
neighbor <PE Loopback ip address> prefix-list DENY-TO-COMCAST o
routing-options {
static {
route 172.16.1.0/24 {
next-hop 172.17.3.1;
retain;
no-readvertise;
}
}
autonomous-system 62736;
}
protocols {
bgp {
group external-peers {
type external;
export Landmark_Export;
neighbor 132.198.255.210 {
description V-Tel_Inet-2;
peer-as 1351;
}
neighbor 216.66.110.77 {
description V-Tel_Internet;
peer-as 17356;
}
neighbor 4.53.87.245 {
description Century_Link;
peer-as 3356;
}
policy-options {
prefix-list Landmark_BGP_Export {
198.54.211.0/24;
}
policy-statement Landmark_Export {
term advertise_Landmark {
from {
prefix-list Landmark_BGP_Export;
}
then accept;
}
then reject;
}
}