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Can site to site file transfers be added to the QoS policy

Hawk
Level 1
Level 1

We have a large MPLS enviromnet with a lot of sites using low bandwidth links.  Alot of these sites are using VoIP which is currently being prioritized in our QoS policies on IOS devices.  If a low bandwidth site retreives a large file from another site that would actually be Rx (download) traffic on the router of the site retrieving the file.  Would this be as simple as adding the IP of the device(s) doing the download to the QoS policy? Would a file download affect voice quality since it is on the same policy?  Would I need to apply a new inbound QoS policy to the interface that is passing the download to the requesting device? In this case it would be the WAN interface.  QoS is currently applied in the outbound direction of the WAN interface for voice.  Here is my current config for the site downloading the file.

 

 

interface Serial2/0
ip address 1.1.1.1 255.255.255.252
encapsulation ppp
dsu bandwidth 44210
service-policy output CL-VOICE_AND_DATA

class-map match-any RATELIMIT_CLASS_1
match access-group name HOST-X
class-map match-any Voice
match dscp ef
match ip precedence 5
match protocol rtp
match access-group 30

policy-map CL-VOICE_AND_DATA
class Voice
priority percent 80
set ip precedence 5
class RATELIMIT_CLASS_1
police rate percent 50 peak-rate percent 60
conform-action transmit
exceed-action drop
violate-action drop
class class-default
fair-queue
random-detect
set ip precedence 0
queue-limit 256 packets

access-list 30 remark Tag as EF Traffic
access-list 30 permit 10.220.153.24

2 Replies 2

balaji.bandi
Hall of Fame
Hall of Fame

What is your WAN bandwidth capacity, what is the % of bandwidth you looking to commit for VoIP all the time so there is no Voice issue occurs when the other Services over utilizing the links ?

 

Based on the information we can suggest configuration.

 

 

 

BB

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Joseph W. Doherty
Hall of Fame
Hall of Fame
Sorry, solving the issue you're dealing with is a bit more involved.

Whenever you have a multiple node (some kind of mesh) topology, you often encounter the problem that the sum of multiple nodes sending to one node can overrun the receiving node's bandwidth. The general QoS "fix" is a QoS policy on the service provider's egress link to each node. MPLS vendors often support this, some charge extra to provide it. Such a QoS policy does not preclude the common need also for a QoS policy on your equipment's egress link to the service provider's network.

If the foregoing isn't possible, then what can guarantee bandwidth management would be every node having a policy that limits the bandwidth that can be sent to every other mode, and the bandwidth allocations of all the nodes allocations don't exceed the available bandwidth to each specific node. For example, if you have a four node network, and one of those nodes had 2 Mbps of traffic, the aggregate of the three other nodes' policies should not exceed 2 Mbps to that 2 Mbps node. As might be imagined, this doesn't scale very well, and you often have much unused bandwidth.

Another "solution" is to rate limit traffic on ingress from the provider. For example, traffic like your heavy file copy, in your OP, would limited to 50% of the ingress bandwidth. Besides, again, you'll find bandwidth often going unused, upstream bandwidth hogs will often (repeatedly) burst a link to capacity before slowing because of detected drops (due to the rate limiter). I.e. this "solution", really isn't one.

Yet another "solution" involves using a traffic bandwidth management appliance (I'm unaware of any in Cisco's product lines, but there are some 3rd party devices for this). Such devices will manipulate what the sender's "sees" as the size of a receiver's RWIN and/or delay sending TCP ACKs. This "solution" will generally work better than an ingress rate limiter, but such traffic appliances aren't always 100% good for reasons I won't go into. (Although, it should be noted, they do confer some other advantages, which I also won't go into.)

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