what is the difference between layer 2 and layer 3 qos
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Answer / trilokchand kilari
Well, none of the above answers talk about QOS,
L2-QOS:
-------
It is clear that L2 is at MAC layer. In case of MAC level
forwarding such as Bridge connction and a quality of
service need to be assured, The following methods can be
used:
1) MAC filtering (avoiding unnecessary traffic coming from
known MAC sources)
2) VLAN & COS: VLAN will ensure that the traffic is
classified based on various parameters like MAC address,
incoming port, etc... COS: Class Of Service is a filed in
VLAN header. This will be used to prioritize traffic. Later
a QOS scheduler can use the COS filed to qualify the
traffic in to different QOS queues.
L3 - QOS
--------
L3 QOS is required for IP level classification.
Classification can be achieved by Diffserv implementations
that takes many IP parameters in to consideration in
prioritizing traffic. This priority can be set in TOS field
of IP header. This TOS will later be used by Scheduling
process to achieve QOS.
| Is This Answer Correct ? | 101 Yes | 6 No |
Answer / shri
L2QoS deals with classification based on Class of
service,MAC based filtering,VPLS QoS.
L3QoS deals with classification based on IP
header(DSCP/Precedence),ACL based filtering,MPLS QoS,etc.
Cisco-engineer.
| Is This Answer Correct ? | 55 Yes | 6 No |
Answer / harsha
L2 QoS is called as CoS (class of service) .
It deals with VLan mapping .Actually in dot1q , u will have
Priority bits (3 bits-2 to the power 3=8 nos).
QoS (called Quality of Service) deals with IP pkt, which
needs to deal with IP headers (ToS).ip precedence bits/dscp
etc.
| Is This Answer Correct ? | 33 Yes | 16 No |
Answer / quadccie
layer 2 QoS uses CoS( class of service) and deals with mac address like-------
*mac address filter
*mac address mapping
*avoid mac address flooding
layer 3 QoS uses ToS ( type of service ) and deals with ip address like-------
*ip precedence
*usually known as DSCP
*uses af values
*mainly used for VOICE PACKETS
| Is This Answer Correct ? | 13 Yes | 3 No |
Answer / hari gundala
Layer 2 belongs to LAN (intranet ) and Layer 3 belongs to
WAN(internet)
| Is This Answer Correct ? | 43 Yes | 107 No |
Answer / venkatesh
LAYER 2 LAYER 3
LAYER 2 DEVICE IS SWITCH LAYER 3 DEVICE IS ROUTER
SWITCH DEALS WITH MAC ADDRESS ROUTER DEALS WITH IP
ADDRESS
USED TO CONNECT DIFFERENT EXPANSION WITH IN A N\W
NETWORK
DATA ARE IN PACKETS DATA ARE IN FRAME
| Is This Answer Correct ? | 24 Yes | 128 No |
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