EIGRP vs Multilink for Load Balancing

[o_unzueta]

I'm planning on implement a solution of VoIP over a 2 parallel WAN links.

Because the bandwidth on both links is less than 512kbps, its important to load balance the traffic between both.

EIGRP its implemented over all the network, so i have the option to use variance to load balance between this links (512kbps and 384kbps)

My second option is tu join both link with MULTILINK.

I want to know which of this options is recomended considering that Data and VoIP will go trought this conection.

Anothe consideration is that i need to implement QoS.

Thanks

Osvaldo U.

[ryanticer · Accepted solution]

Hello,

My personal recommendation is to use EIGRP. EIGRP has a feature called Unequal Cost Load Balancing, which basically unequally loads the links between two neighbors based on the link's bandwidth. In the event that one link goes down, EIGRP would immediately redirect all flow over a single link.

Please note that EIGRP is a proprietary routing protocol, so if an ISP is involved between the endpoints, it is unlikely to be supported (look at MLPPP some more) and that with low-bandwidth links, some pretty aggresive QoS settings involving Weighted Random Early Detection (WRED), and Low Latency Queuing (LLQ) will definitely be needed to make the links usable with the lowest amount of jitter as possible.

Something like...

router eigrp

network

network

variance 5

no auto-summary

!

class-map voicestream

match ef

!

policy-map wan512

class voicestream

  priority 200

class class-default

  fair-queue

  random-detect dscp-based

!

policy-map wan384

class voicestream

  priority 153

class class-default

  fair-queue

  random-detect dscp-based

!

interface serial0/0

  ip address

  service-policy out wan512

  max-reserved-bandwidth 90

!

interface serial0/1

  ip address

  service-policy out wan384

  max-reserved-bandwidth 90

!

Ryan