02-11-2007 05:29 PM
Hi,
We currently have dual links between our core routers (7206VXRs) - Primary being ATM, and secondary being Ethernet - At present, Ethernet is only used if ATM fails(This is achieved via OSPF)....we presently only have mpls enabled on the ATM links.
We are wanting to make more efficient use of the backup ethernet links(As they are expensive)....hoping that TE is the correct(best practice) option.
Our current bandwidth is as follows:
ATM - 8Mb
Ethernet - 4Mb
Our goal is to (hopefully) have a total of 12Mb bandwidth available for use(i.e. Load-share over both the ATM+Ethernet links)......Is FRR necessary in what we are wanting to achieve?
Proposed config for one of the Core routers...
mpls traffic-eng tunnels
no mpls traffic-eng auto-bw timers frequency 0
tag-switching tdp router-id Loopback0
router ospf 100
mpls traffic-eng router-id Loopback0
mpls traffic-eng area 0
interface FastEthernet2/0
description Point-to-Point Link SYD
bandwidth 4000
ip address xxx.xxx.xxx.197 255.255.255.252
ip ospf message-digest-key 10 md5 blah
### Would this still be required?
ip ospf cost 100
tag-switching ip
tag-switching mtu 1520
service-policy output TRUNK-TO-SYD
mpls traffic-eng tunnels
### Not too sure about this?
ip rsvp bandwidth ? ?
interface ATM1/0.100 point-to-point
description TRUNK LINK TO SYD
bandwidth 8000
ip address xxx.xxx.yyy.2 255.255.255.252
ip ospf message-digest-key 10 md5 blah
tag-switching ip
service-policy output TRUNK-TO-SYD
mpls traffic-eng tunnels
### Not too sure about this?
ip rsvp bandwidth ? ?
interface Tunnel2
description primary tunnel2 ERT01-BNE->ERT01-SYD
ip unnumbered Loopback0
no ip directed-broadcast
tag-switching ip
tunnel destination xxx.xxx.yyy.248
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng autoroute announce
tunnel mpls traffic-eng priority 7 7
### Not too sure about this?
tunnel mpls traffic-eng bandwidth ?
tunnel mpls traffic-eng path-option 5 dynamic
Apprecaite all assisntance.
02-12-2007 04:28 AM
ok mate rsvp bancwidth is the max you will allow reserved (If needed) down an interface.
Tunnel bandwidth is how much bandwidth should your tunnel be looking for.
e.g.
RSVP = 100meg
Tunnel wants 80 meg
This will work
RSVP=10 meg
Tunnel wants 20 meg <-- tunnel will never come up.
HTH
02-12-2007 01:43 PM
Thanks mate - So I would be looking at something like(Three 4Mb tunnels running between the 7200's):
mpls traffic-eng tunnels
tag-switching tdp router-id Loopback0
router ospf 100
mpls traffic-eng router-id Loopback0
mpls traffic-eng area 0
interface FastEthernet2/0
description Point-to-Point Link SYD
bandwidth 4000
ip address xxx.xxx.xxx.197 255.255.255.252
ip ospf message-digest-key 10 md5 blah
ip ospf cost 100
tag-switching ip
tag-switching mtu 1520
service-policy output TRUNK-TO-SYD
mpls traffic-eng tunnels
ip rsvp bandwidth 4000 4000
interface ATM1/0.100 point-to-point
description TRUNK LINK TO SYD
bandwidth 8000
ip address xxx.xxx.yyy.2 255.255.255.252
ip ospf message-digest-key 10 md5 blah
tag-switching ip
service-policy output TRUNK-TO-SYD
mpls traffic-eng tunnels
ip rsvp bandwidth 8000 8000
interface Tunnel2
description primary tunnel2 ERT01-BNE->ERT01-SYD
ip unnumbered Loopback0
no ip directed-broadcast
tag-switching ip
tunnel destination xxx.xxx.yyy.248
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng autoroute announce
tunnel mpls traffic-eng priority 7 7
tunnel mpls traffic-eng bandwidth 4000
tunnel mpls traffic-eng path-option 5 dynamic
interface Tunnel3
description primary tunnel3 ERT01-BNE->ERT01-SYD
ip unnumbered Loopback0
no ip directed-broadcast
tag-switching ip
tunnel destination xxx.xxx.yyy.248
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng autoroute announce
tunnel mpls traffic-eng priority 7 7
tunnel mpls traffic-eng bandwidth 4000
tunnel mpls traffic-eng path-option 5 dynamic
interface Tunnel4
description primary tunnel4 ERT01-BNE->ERT01-SYD
ip unnumbered Loopback0
no ip directed-broadcast
tag-switching ip
tunnel destination xxx.xxx.yyy.248
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng autoroute announce
tunnel mpls traffic-eng priority 7 7
tunnel mpls traffic-eng bandwidth 4000
tunnel mpls traffic-eng path-option 5 dynamic
02-12-2007 02:37 PM
Hi,
as load sharing over TE tunnels is done by CEF and unequal cost is taken into account, onl two tunnels are needed. So create one 4 Mbps and one 8 Mbps Tunnel (or 800 kbps and 400 kbps with the same result) and route them over the respective links. Do not forget about the return path!
Regards, Martin
02-12-2007 02:47 PM
Hi Martin,
Are you suggesting I do something like:
int tun3
tunnel mpls traffic-eng bandwidth 8000
tunnel mpls traffic-eng path-option 1 explicit name tunnel_3 lockdown
ip explicit-path name tunnel_3 enable
next-address xxx.xxx.xxx.1
02-12-2007 10:53 PM
Yes. you do not need to lockdown the 8 Mbps tunnel, it will only find one path anyhow. Make sure the 4 Mbps tunnel does not have higher hold priority than the setup priority of the bigger tunnel any they sould end up in the prefered links.
CEF will do te load sharing based on reserved bandwidth, i.e. 2:1 though IP routing will see two parallel equal cost pathes. Make sure the tunnel is announced to IP routing (autoroute announce) and has better metric than the physical path (relative metric -1).
Regards, Martin
02-13-2007 01:38 PM
Thanks Martin.
One question - Why do you suggest to use explicit, rather than dynamic path selection?
And under each tunnel to have a better metric, I would have:
tunnel mpls traffic-eng autoroute metric relative -1
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