03-20-2012 02:56 PM - edited 03-04-2019 03:44 PM
I have traffic coming into a 4948 switch with 2 ports going to 2 different 7200 routers.
There is traffic flowing from multiple VLANS. One of these uses L2TPv3 tunneling to get to a far-end gateway router.
Each 7200 has a DS3 which connect to two other 7200s which connect to a 4948 on the far end.
Also connected to the far-end 4948 is the WAN traffic gateway 7200.
We are using OSPF within the network so the routers can learn where the Loopback interface of the far-end gateway 7200 is.
Right now traffic is only going through one near-end 7200 and through its DS3.
We would like to balance the load between the two routers and the two DS3s.
Is it possible to use GLPB to accomplish this?
I may not have explained this properly but would try and answer any questions in order to help someone understand it better.
I currently have live customer traffic so can't really "experiement" with it live.
Thanks,
Caryl
03-20-2012 03:15 PM
Yes you can do it.
The one thing is, if I understood well the near-end 7200 are conncted to the local switch and to the DS3 links.So the near-end 7200 are not connected back to back.
Having this in mind you should track the DS3 link or the existence of the lookback of the far end 7200 , in order to decrement the AVF priority. If not you will have a near-end 7200 as a black hole for some user's traffic in the case of link failure (DS3) or other.
Regards
Dan
03-20-2012 03:19 PM
You are correct there are no direct connections between the near-end 7200s.
I am working on a diagram to upload as well.
03-20-2012 03:25 PM
OK then , the main worry will be :
- near-end 7200 looses the connection to the far-end 7200 ( DS3 link, or other equipment /link on the path )
but it will still be the AVF . As a solution I think you can track ip route existence of the far-end 7200's loopback, and using this track you should lower the priority. This way if it looses the connection to far end will not be AVF.
A better solution , i think , is to add a back to back interface between near end 7200, you will have a better redundancy.
Regards
Dan
03-22-2012 04:40 PM
OK, here is a network map and the appropriate configs.
I think I have all the IPs and VLANS changed to protect the innocent.
I tried to color code the configs but it was lost in the paste.
The near end routers do have a connection into the same switch so not sure why you think I would need another connection between them.
Thanks again for any insight into deploying GLBP to utilize the idle DS3.
I do know that there will need to be additional interfaces created on the 2nd path that are not there today.
Caryl
INTERNET GW________________________________
interface GigabitEthernet0/1
description Co-located @ Cabinet 100-104
ip address xx.xxx.238.130 255.255.255.248 secondary
ip address xx.xxx.234.34 255.255.255.248
ip route-cache flow
no ip mroute-cache
duplex auto
speed auto
media-type rj45
no negotiation auto
no cdp enable
interface GigabitEthernet0/2
no ip address
duplex auto
speed auto
media-type rj45
no negotiation auto
interface GigabitEthernet0/2.200
description FAR-NEAR VLAN
encapsulation dot1Q 200
ip address xx.xxx.238.193 255.255.255.192
ip route 0.0.0.0 0.0.0.0 xx.xxx.238.129
FAR SW________________________________________________
interface GigabitEthernet0/1
description connected to far-gw
switchport mode trunk
interface GigabitEthernet0/2
description connection to far-gw2
switchport mode trunk
interface GigabitEthernet0/3
description to internet-gw
switchport mode trunk
FAR GW________________________________________________
pseudowire-class vlan-connect
encapsulation l2tpv3
protocol l2tpv3 class1
ip local interface Loopback0
interface Loopback0
ip address xx.xxx.254.161 255.255.255.255
interface Serial2/0
description DS3 to NEAR-GW
bandwidth 44210
ip address xx.x.0.10 255.255.255.252
ip broadcast-address xx.x.0.11
ip load-sharing per-packet
no ip route-cache cef
no ip route-cache
ip ospf authentication-key
ip ospf cost 25
ip ospf hello-interval 6
ip ospf dead-interval 20
dsu bandwidth 44210
framing c-bit
cablelength 10
down-when-looped
serial restart-delay 0
interface GigabitEthernet5/0
description connection to far-sw
mtu 4470
no ip address
no ip route-cache cef
no ip route-cache
ip ospf cost 9
negotiation auto
interface GigabitEthernet5/0.200
description VLAN 200 near tunnel
encapsulation dot1Q 200
no ip route-cache
no cdp enable
xconnect xx.xxx.254.81 200 pw-class vlan-connect
router ospf 1
log-adjacency-changes
redistribute static metric-type 1 subnets route-map LINK-PRIORITY-STATIC
network xx.x.0.0 0.0.0.3 area 0.0.0.0
network xx.x.0.4 0.0.0.3 area 0.0.0.0
network xx.x.0.8 0.0.0.3 area 0.0.0.0
network xx.x.0.32 0.0.0.3 area 0.0.0.0
network xx.xx.90.0 0.0.0.255 area 0.0.0.0
network xx.xxx.254.161 0.0.0.0 area 0.0.0.0
maximum-paths 6
distribute-list 35 out static
distance 40
access-list 35 permit any
route-map LINK-PRIORITY-STATIC permit 65535
match ip address 1
FAR GW2_______________________________________________________
pseudowire-class vlan-connect
encapsulation l2tpv3
protocol l2tpv3 class1
ip local interface Loopback0
interface Loopback0
ip address xx.xxx.254.162 255.255.255.255
interface Serial2/0
description DS3 to NEAR-GW2
bandwidth 44210
ip address xx.x.0.14 255.255.255.252
ip broadcast-address xx.x.0.15
ip load-sharing per-packet
no ip route-cache cef
no ip route-cache
ip ospf authentication-key
ip ospf cost 25
ip ospf hello-interval 6
ip ospf dead-interval 20
dsu bandwidth 44210
framing c-bit
cablelength 10
down-when-looped
serial restart-delay 0
interface GigabitEthernet5/0
description connection to far-sw
mtu 4470
no ip address
no ip route-cache cef
no ip route-cache
ip ospf cost 9
negotiation auto
router ospf 1
log-adjacency-changes
redistribute static metric-type 1 subnets route-map LINK-PRIORITY-STATIC
network xx.x.0.12 0.0.0.3 area 0.0.0.0
network xx.x.0.16 0.0.0.3 area 0.0.0.0
network xx.x.0.24 0.0.0.3 area 0.0.0.0
network xx.xx.90.0 0.0.0.255 area 0.0.0.0
network xx.xxx.254.162 0.0.0.0 area 0.0.0.0
maximum-paths 6
distribute-list 35 out static
distance 40
access-list 35 permit any
route-map LINK-PRIORITY-STATIC permit 65535
match ip address 1
NEAR GW_______________________________________________
interface Loopback0
ip address xx.xxx.254.81 255.255.255.255
interface GigabitEthernet0/2
description VLAN Trunk to near-sw
mtu 4470
no ip address
duplex auto
speed auto
media-type rj45
no negotiation auto
interface GigabitEthernet0/2.200
description VLAN 200 near tunnel to far
encapsulation dot1Q 200
no cdp enable
xconnect xx.xxx.254.161 210 pw-class vlan-connect
interface Serial4/0
description DS3 to FAR-GW
ip address xx.x.0.9 255.255.255.252
ip ospf authentication-key
ip ospf cost 25
ip ospf hello-interval 6
ip ospf dead-interval 20
dsu bandwidth 44210
framing c-bit
cablelength 10
serial restart-delay 0
router ospf 1
log-adjacency-changes
redistribute static metric-type 1 subnets route-map LINK-PRIORITY-STATIC
network xx.x.0.8 0.0.0.3 area 0.0.0.0
network xx.x.2.0 0.0.0.3 area 0.0.0.0
network xx.x.3.0 0.0.0.3 area 0.0.0.0
network xx.x.3.4 0.0.0.3 area 0.0.0.0
network xx.x.3.8 0.0.0.3 area 0
network xx.x.3.12 0.0.0.3 area 0.0.0.0
network xx.x.3.76 0.0.0.3 area 0.0.0.0
network xx.x.3.80 0.0.0.3 area 0.0.0.0
network xx.x.3.84 0.0.0.3 area 0.0.0.0
network xx.x.3.88 0.0.0.3 area 0.0.0.0
network xx.x.3.128 0.0.0.0 area 0
network xx.x.3.132 0.0.0.3 area 0.0.0.0
network xx.x.3.128 0.0.0.63 area 0.0.0.0
network xx.xx.xx.x 0.0.0.255 area 0.0.0.0
network xx.xx.11.0 0.0.0.255 area 0.0.0.0
network xx.xx.12.0 0.0.0.255 area 0.0.0.0
network xx.xx.15.0 0.0.0.255 area 0.0.0.0
network xx.xxx.254.81 0.0.0.0 area 0.0.0.0
maximum-paths 6
default-information originate metric 2000
distribute-list 30 out static
distance 40
access-list 30 permit any
route-map LINK-PRIORITY-STATIC permit 65535
match ip address 1
NEAR GW2______________________________________________
interface Loopback0
ip address xx.xxx.254.82 255.255.255.255
interface GigabitEthernet1/0
mtu 4470
no ip address
negotiation auto
interface Serial4/0
description DS3 to FAR-GW2
ip address xx.x.0.13 255.255.255.252
ip ospf authentication-key
ip ospf cost 25
ip ospf hello-interval 6
ip ospf dead-interval 20
dsu bandwidth 44210
framing c-bit
cablelength 10
serial restart-delay 0
router ospf 1
log-adjacency-changes
redistribute static metric-type 1 subnets route-map LINK-PRIORITY-STATIC
network xx.x.0.12 0.0.0.3 area 0.0.0.0
network xx.x.3.64 0.0.0.3 area 0.0.0.0
network xx.x.3.68 0.0.0.3 area 0.0.0.0
network xx.x.3.72 0.0.0.3 area 0.0.0.0
network xx.x.3.76 0.0.0.3 area 0.0.0.0
network xx.x.3.80 0.0.0.3 area 0.0.0.0
network xx.x.3.84 0.0.0.3 area 0.0.0.0
network xx.x.3.88 0.0.0.3 area 0.0.0.0
network xx.x.3.132 0.0.0.3 area 0.0.0.0
network xx.xx.xx.x 0.0.0.255 area 0.0.0.0
network xx.xx.11.0 0.0.0.255 area 0.0.0.0
network xx.xx.12.0 0.0.0.255 area 0.0.0.0
network xx.xx.15.0 0.0.0.255 area 0.0.0.0
network xx.xxx.254.82 0.0.0.0 area 0.0.0.0
maximum-paths 7
distribute-list 30 out static
distance 40
access-list 30 permit any
route-map LINK-PRIORITY-STATIC permit 65535
match ip address 1
NEAR SW___________________________________________________
interface Loopback0
ip address xx.xxx.254.83 255.255.255.255
interface GigabitEthernet1/2
description Trunk interface to near-gw
switchport trunk encapsulation dot1q
switchport mode trunk
mtu 4470
interface GigabitEthernet1/6
description connection to near-gw2
switchport trunk encapsulation dot1q
switchport mode trunk
mtu 4470
interface GigabitEthernet1/33
description Calix C7 Internet Uplink
switchport trunk encapsulation dot1q
switchport mode trunk
CALIX_______________________________________________
Virtual Router
IP IF RTRAID N1-1-VR10 (NEAR CO) xx.xxx.238.194 255.255.255.192 VLAN 200
IP ROUTE xx.xxx.238.192 255.255.255.192 xx.xxx.238.194
DSL CUSTOMER______________________________
Modem Config
IP xx.xxx.238.196 S/M 255.255.255.192 GW xx.xxx.238.193
03-22-2012 04:50 PM
Hi ,
My reason for the 2nd interface between near-end routers is GLBP. If for example near-gw looses the connection with far-gw , it will still be AVF - being the gateway for some clients - as far I understoood from your setup is that the only routes that near-gw will have - beside those connected - will be received from far-gw. In the case decribed , you will not have any routes, so the traffic will be droped on this router (near-gw)
You can also activate ospf , on the interface's toward the clients.
Regards
Dan
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