Tips For Optimizing Your WAN (Wide Area Network)

So you're looking to optimize your WAN for your business and need to know what your options are. Upgrading your bandwidth to MPLS or Ethernet isn't necessarily the solution. Bandwidth utilization is the key for optimizing your WAN.

Packeteer, Riverbed and Juniper are WAN optimization systems that do an excellent job with latency, especially if CIFS WAN-unaware situations such as opening, copying and modifying files using Windows are the main problem.

To identify the delay, you need to find the path your IP packets take. A satellite connection versus a landline connection (such as earthbound wireless, land or underwater fibre) can be the source of the latency problem. Check with your service provider to get a service level agreement to guarantee the quality parameters you want concerning packet loss, delay and jitter.

It's very important to not buy or install any new network system before identifying existing delays.

Once the latency issue is identified, a valid solution for optimizing your WAN is to purchase a WAN-accelerator from a vendor that offers such a product. The amount of traffic your WAN uses will also determine which vendor you will choose for this product. For example, if your business uses such programs as Citrix and SAP, then a traffic-prioritizing WAN accelerator such as Packeteer or Ipanema would be the best solution. But if your business uses more file-oriented applications, your best option would be to purchase a data reduction accelerator like Riverbed, Juniper Citrix and Cisco. Riverbed is by far the best solution.

While optimization systems effect only TCP flows, latency issues with UDP flows (VoIP) can't be resolved since real-time traffic is naturally subject to delays. Citrix WANScaler, Cisco WAAS, Juniper, Riverbed and Expand as well as other vendors sell systems for optimizing generic TCP flows which would meet the needs of your business.

As a word of caution, all the vendors hide the effects of latency. WAN optimization solutions act like an invisible TCP proxy, simultaneously spoofing both the server's IP address to the client and the client's IP address to the server. The TCP ACK messages are sent locally, speeding up the delivery of the ACK message and avoiding latency effects. TCP connections and throughput are subject to latency when the ACK messages are returned.

Vendors also hide the effects of latency by utilizing the entire WAN bandwidth link for implementing selective ACKs and large initial flow control windows. Compression mechanisms, layer 7 optimizations (mostly CIFS file-sharing as well as HTTP-based compression), embedded QoS are used for artificially increasing bandwidth not in use. This is known as "WAN optimization".
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