| So you're looking to optimize your WAN for your | | | | more file-oriented applications, your best option would |
| business and need to know what your options are. | | | | be to purchase a data reduction accelerator like |
| Upgrading your bandwidth to MPLS or Ethernet isn't | | | | Riverbed, Juniper Citrix and Cisco. Riverbed is by far |
| necessarily the solution. Bandwidth utilization is the | | | | the best solution. |
| key for optimizing your WAN. | | | | While optimization systems effect only TCP flows, |
| Packeteer, Riverbed and Juniper are WAN | | | | latency issues with UDP flows (VoIP) can't be |
| optimization systems that do an excellent job with | | | | resolved since real-time traffic is naturally subject to |
| latency, especially if CIFS WAN-unaware situations | | | | delays. Citrix WANScaler, Cisco WAAS, Juniper, |
| such as opening, copying and modifying files using | | | | Riverbed and Expand as well as other vendors sell |
| Windows are the main problem. | | | | systems for optimizing generic TCP flows which |
| To identify the delay, you need to find the path | | | | would meet the needs of your business. |
| your IP packets take. A satellite connection versus a | | | | As a word of caution, all the vendors hide the |
| landline connection (such as earthbound wireless, land | | | | effects of latency. WAN optimization solutions act |
| or underwater fibre) can be the source of the | | | | like an invisible TCP proxy, simultaneously spoofing |
| latency problem. Check with your service provider to | | | | both the server's IP address to the client and the |
| get a service level agreement to guarantee the | | | | client's IP address to the server. The TCP ACK |
| quality parameters you want concerning packet loss, | | | | messages are sent locally, speeding up the delivery |
| delay and jitter. | | | | of the ACK message and avoiding latency effects. |
| It's very important to not buy or install any new | | | | TCP connections and throughput are subject to |
| network system before identifying existing delays. | | | | latency when the ACK messages are returned. |
| Once the latency issue is identified, a valid solution | | | | Vendors also hide the effects of latency by utilizing |
| for optimizing your WAN is to purchase a | | | | the entire WAN bandwidth link for implementing |
| WAN-accelerator from a vendor that offers such a | | | | selective ACKs and large initial flow control windows. |
| product. The amount of traffic your WAN uses will | | | | Compression mechanisms, layer 7 optimizations |
| also determine which vendor you will choose for this | | | | (mostly CIFS file-sharing as well as HTTP-based |
| product. For example, if your business uses such | | | | compression), embedded QoS are used for artificially |
| programs as Citrix and SAP, then a traffic-prioritizing | | | | increasing bandwidth not in use. This is known as |
| WAN accelerator such as Packeteer or Ipanema | | | | "WAN optimization". |
| would be the best solution. But if your business uses | | | | |