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A MPLS network with 6500 series switches on distribution and also on core layer,Acting as a PE.

CE---DS_SW/PE-----Core_SW P/PE----ISP/PE

Client are connected to distribution switch(PE)and traffic is label switch between distribution and core switch.The connectivity between the ISP/PE and our core switch is configured as back -to- back VRF for each client VRF connected to distribution switch.

I want to implement a QOS on egress interface of each VRF of core because i have a 10 GIG link between distribution and core switch.AS a connection to ISP is a back to back VRF the packet will be a IPV4 packet???? correct me if am wrong????so the normal QOS tools such as bandwith limitation for each VRF interface on core can be implemented?? Am i write???

But when i will receive a traffic from ISP router which is connecting to my core router VRF interface,what QOS tool i have to apply on my core router a mpls QOS??? or i should recieve and pass it on distribution switch as it is am receiving form ISP router.

i need to apply QOS for traffic coming from other end or i shld pass it on as it is to distribution switch????

Am new to QOS i have read books but am not sure.

Hall of Fame Super Silver


Hello Adam,

>> AS a connection to ISP is a back to back VRF the packet will be a IPV4 packet????


About the other questions:

you need to control how you send traffic to ISP in order to respect the SLA.

traffic received from the ISP has been already processed by ISP.

depending on the agreements you may need to control the outbound traffic volume for each client/VRF.

For inbound traffic you can only:

accept traffic as it is


you can decide to remark traffic according to policies with each client.

you cannot shape inbound traffic you could police in order to mark down traffic exceeding the SLA.

It is difficult to say more without knowing the details.

Hope to help


Community Member


Hi giuslar

Each client VRF is requesting a dedicated bandwith so on core router my QOS would like:correct me if am wrong.

For example:

class-map match-all voip-rtp

match ip rtp 16384 16383

policy-map queue-voip

class voip-rtp

bandwidth 64

class class-default


interface Serial0/0

service-policy output queue-voip

FOR INBOUND Traffic,definately i have to police for not consuming traffic of other clients??? correct me if am wrong.

But the connection from core to distribution is label switch,the ip packet when it will enter the core it will be a label switch by which QOS uniform mode,pipe mode or short pipe mode.If i untouch the packet,bydefault which QOS will apply so that precedence will be carried further to ip packet to client router.

Community Member


Hello Experts,

Can anybody help me for the query mentioned in above mails.

Community Member


Hi Giuseppe

Awaiting for ur reply.If anything missing please reply.

Hall of Fame Super Silver


Hello Adam,

sorry for having missed your updates on this thread.

if this is not a VRF lite implementation customer traffic is mapped to VPN labels and traffic between distrib and core switches is tagged.

There is no default QoS treatment on core facing MPLS enabled links.

at the edge at customer facing links you need to:

police and mark the different types of traffic.

exceeding traffic can be marked down or even dropped.

MPLS EXP bits will reflect the settings of the TOS byte in the transported IP packet.

then on MPLS facing links you need to configure schedulers based on MPLS EXP bits.

So the QoS will be on the aggregates of all single customers needs:

for example if 10 customers require 64 kbps of voip service each you need to provide for all of this including the additional MPLS overhead.

4 bytes per MPLS label per packet.

50 packets per second

so you may need 656000 bps instead of 640000 bps on the core facing link.

This can be possible or not depending on the type of linecard used because these are multilayer switches.

Some linecards offer only switch oriented queueing other provide modular QoS support.

You may provide a sh module and indication of what is the port that connect distribution to core.

Hope to help


Community Member



The Connection is same as below


The link between distribution and the core is fiber 10 gig i dont want to implement any bandwidth limitation on the links between distribution and the core i want let the customer use the 10 gig link upto the core but on core interfaces facing to ISP which QOS i have to apply traditional QOS or MPLS QOS ????.The packet will be a IPV4 am having a back to back vrf connection with ISP.

question 2:

The traffic which i will recieve from ISP definately i will police that traffic according to CLient demand but when it will travel towards the distribution switch i should implement QOS towards the distribution switch???? or i shld implement MPLS QOS or i shld leave that traffic as default,because i want the 10 Gig link between core and distribution shld be utilize as much as can.Can u advise me what are the drawback for this.

Sorry to reply late,


Hall of Fame Super Silver


Hello Adam,

>> The packet will be a IPV4 am having a back to back vrf connection with ISP.

traditional QoS if IPv4 packets are sent out with an 802.1Q frame.


in direction core to distribution to customer you may be fine with current scenario given that the 10GE is much faster then the WAN link.

Hope to help


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