Switching to VoIP

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Best Practices for Quality of Service

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Best Practices for Quality of Service

When building or expanding a network for Voice over IP, there are many standards

from which to choose, as you can see. Each has distinct characteristics that makes it

good for certain situations. But, in the end, your success with QoS standards can be

only as deep as your use of them is practical. Here’s a list of best practices for ensur-

ing Quality of Service on the network.

Choose the right standards

• Multiple QoS standards can complement one another, but don’t overdo it. Using

MPLS, RSVP, and DiffServ all on a 300-node network, while possible, wouldn’t

be a very practical idea.

• Don’t expect the QoS policies you establish to be supported by legacy routers

and switches.

• If you are coordinating several network managers, departments, or divisions, be

sure you have their buy-in and a mandate to enforce the QoS policy you estab-

lish. Easier said than done, especially in large organizations.

• If your network traffic is more than 70% data to voice, use a packet prioritiza-

tion technique like DiffServ or 802.1p.

• If your network is large (hundreds of voice nodes) and relatively busy, use Diff-

Serv.

• If your network is especially congested or very large (thousands of voice nodes),

use RSVP.

Use the standards ...