QoS Options

QoS Options
Obviously, the ultimate quality of service would be if we were able to guarantee that every
packet/frame on the network were delivered reliably, in the correct sequence, and with zero
delay. Well, guess what? That’s not going to happen! But a variety of techniques can be
applied to try to get close enough to the end of the rainbow to allow the applications to manage
the rest themselves.
QoS Options
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The following parameters are considered essential for measuring and providing any QoS:

Service availability

Frame loss

Frame order

Frame duplication

Transit delay experienced by frames

Frame lifetime

Undetected frame error rate

Maximum service data unit size supported

User priority

Throughput
Two main mechanisms exist for dealing with end-to-end QoS: Differentiated Services and
Integrated Services. Both are contenders for the ultimate solution, but we will focus on Differentiated
Services because that’s what Cisco uses with Ethernet.
The Integrated Services model involves setting up an end-to-end connection
across an internetwork of RSVP-enabled routers using a new IP-based signaling
protocol called Resource Reservation Setup Protocol (RSVP). RSVP routers
request and reserve bandwidth across an internetwork and release it back to
the internetwork after the connection is terminated.