Dual ISP link for failover with QOS for voice and data

[nwekechampion]

Hi all,

I am implementing a solution for a client that requires the use of two wan links, with the secondary one as backup and main as primary. I also need to implement QOS on 20mb link with 19 for data and 1mb for voice.

Please could anyone provide some help as to the best way to implement this?

Just finished my CCNA, but this is a bit out of my depth.

Thanks in advance.

[e.ciollaro · Accepted solution]

Hi

regarding primary and backup it's not clear to me if you are intended to use one router or two, which kind of routing protocol are you going to use over the WAN links and the LAN architecture. Please give some more detail or, even better, attach a network diagram.

QoS for VoIP over WAN link is not easy because it depends on many things, for example the WAN characteristics. Usually I have also to "mark" Voice packet to ensure that QoS is applied all over the WAN network. Generally speaking I would suggest you to configure hierarchical QoS: first shape traffic to 20Mbps and then give 1M to voice using LLQ and 19M to other data traffic. If WAN link support some burst  you could configure something like this:

class-map match-all VoIP
 match access-group name VoIP-acl   

<configure the ACL to match VoIP for example matching the voice VLAN>

policy-map qos
 class VoIP
  priority 1000
 class class-default
  bandwidth 19000
policy-map shaping
 class class-default
  shape average 20000000
  service-policy qos

Better config could distinguish between VoIP signaling and RTP stream and  you should use QoS also over the LAN, probably you have enough bandwidth but I have to ensure also low delay and jitter.

Bye,

e

Please rate if useful

[nwekechampion]

Thanks E.

So sorry for my late reply.

The Primary link is going to go through PPPoE and the backup link via 4g.

I am trying to give voip priority queue at the egress port with 1mb and data lower priority with 19mb.

I have simulated two wan links in GNS3 to get this running. Please could you look at my config below and let me know how I can go about implementing this?

no aaa new-model
no ip icmp rate-limit unreachable
ip cef
!
!
!
ip dhcp excluded-address 10.0.0.1 10.0.0.10
!
ip dhcp pool LAN1
network 10.0.0.0 255.255.255.0
default-router 10.0.0.1
!
!
!
no ip domain lookup
no ipv6 cef
!
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
ip tcp synwait-time 5
!
track 8 ip sla 1 reachability
!
!
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
description Towards Customer LAN
ip address 10.0.0.1 255.255.255.0
ip nat inside
duplex full
!
interface POS1/0
description Primary Link to ISP1
ip address 200.55.60.2 255.255.255.0
ip nat outside
shutdown
!
interface FastEthernet2/0
no ip address
shutdown
duplex full
!
interface FastEthernet3/0
no ip address
shutdown
duplex full
!
interface POS4/0
description Backup Link to ISP2
ip address 201.55.60.2 255.255.255.252
ip nat outside
!
ip nat inside source route-map NAT_ISP1 interface POS1/0 overload
ip nat inside source route-map NAT_ISP2 interface POS4/0 overload
ip forward-protocol nd
!
!
no ip http server
no ip http secure-server
ip route 0.0.0.0 0.0.0.0 200.55.60.1 track 8
ip route 0.0.0.0 0.0.0.0 201.55.60.1 10
!
ip sla 1
icmp-echo 200.55.60.1 source-ip 200.55.60.2
ip sla schedule 1 life forever start-time now
access-list 101 permit ip 10.0.0.0 0.0.0.255 any
!
route-map NAT_ISP2 permit 10
match ip address 101
match interface POS4/0
!
route-map NAT_ISP1 permit 10
match ip address 101
match interface POS1/0
!
!
!
control-plane
!
!
line con 0
exec-timeout 0 0
privilege level 15
logging synchronous
stopbits 1
line aux 0
exec-timeout 0 0
privilege level 15
logging synchronous
stopbits 1
line vty 0 4
login
!
!
end

[e.ciollaro · Accepted solution]

Hi,

I guess you can't configure an IGP to receive the default network from ISP1 (did you ask them if it is possible ?) so track could be appropriate. Obviously for production network you will configure a dialer for pppoe.

Over the WAN interface apply the LLQ (see my previous post)  using

interf ...

   service-policy shaping out

Bye,

enrico.

PS: rate if useful

[nwekechampion]

Hi E,

How are you?

Please could you point me to any document/video that can give me a qucik intro to voip on a basic level?

Thank you.