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Shape average"  and    "RSPV cisco

dhikra-marghli8
Level 1
Level 1

Hello

what's the difference between  Shape average"  and    "RSPV    in network  cisco  ?  

I wait a answer from expert network ? 

Thanks 

 

4 Accepted Solutions

Accepted Solutions

A typical use case for using a shaper. . .

Suppose you have an ISP which provides a physical hand-off with much more bandwidth than you're allowed to use.  Common cases would be DSL, Fios, Cable, where you might only have a faction of the physical bandwidth as an allowance.  For example, you have a gig connection, but your bandwidth allowance is 200 Mbps.

Now what happens if you send 300 Mbps, on a gig connection, where your bandwidth allowance is 200 Mbps?

Generally, your ISP will drop 100 Mbps of your 300 Mbps.  But do you know when this happens?

What you might do, is place a 200 Mbps shaper on the gig interface.  Then you will see drops.  Further, you have the option to use QoS to determine what traffic will be dropped first.

As for common example of RSVP usage, I've never seen a real world implementation.

In theory, if your network application and network are configured to support RSVP, a possible good use case example would be you with to do a tele-meeting with some across the network.

So, what should happen, your tele-meeting network application requests the network to guarantee (reserve) the bandwidth it needs between the two tele-meeting network hosts.  All in-path network devices, need to participate and agree they can, and will, guarantee the bandwidth requested.  If any do not, the connection is not made.  But, if it is made, assuming your tele-meeting truly only needs the bandwidth it requested, it should operate flawlessly.

You might want to read this Cisco information; take note of RSVP in the IntServ model.

You might also find this Cisco TechNote helpful, as it explains a bit about how shaping, and its alternative policing, work.

I also recommend searching the Internet and/or Cisco sites, for (much) more (available) information on RSVP and/or shaping.

You also will likely find these Cisco forums most helpful when having a specific issue, like for shaping, perhaps, for example, how best to set Bc for a particular traffic type.  I.e. things not often found even with extensive Internet searches.

View solution in original post

M02@rt37
VIP
VIP

Hello @dhikra-marghli8 

Traffic shaping is a mechanism used to control the rate of data transmission in a network. With "shape average," traffic is smoothed out over time to conform to a specified average rate. This means that bursts of traffic are limited, ensuring that the overall transmission rate remains within the configured average rate. Traffic shaping is commonly used to regulate the flow of traffic at the edge of a network, such as at a router interface connected to an ISP, to prevent congestion and ensure fair use of bandwidth.

RSVP is a signaling protocol used in computer networks to enable the reservation of network resources for specific data flows. With RSVP, devices along a data path can reserve bandwidth and other resources to ensure that sufficient capacity is available for the transmission of data. RSVP is commonly used in QoS implementations (IntServ) to prioritize certain types of traffic, such as real-time voice or video, and to guarantee quality of service requirements are met. Unlike traffic shaping, RSVP involves the explicit reservation of resources along the data path rather than smoothing out traffic over time.

 

Best regards
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View solution in original post

 @dhikra-marghli8, let's clarify.

As concerned, average shaping and burst (Bc), when you configure average shaping, you are essentially specifying the average rate at which traffic is allowed to be sent. The Burst (Bc) is the amount of data that can be sent in a single burst at the specified rate. If the traffic rate exceeds the configured average rate (Bc), the excess traffic is typically buffered in a queue. This excess traffic will be sent out at a later time, adhering to the specified average rate.

Behavior When Traffic exceeds shaping rate ?
If the incoming traffic rate exceeds the configured shaping rate (Bc), the excess traffic is typically queued. The router will attempt to send the excess traffic later, according to the configured shaping parameters.

Typically, traffic shaping is configured on the egress interface of a router where the traffic needs to be shaped. This could be done at the customer premises equipment (CPE) or within the provider edge (PE) router in the backbone, depending on the network design.

 

Best regards
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View solution in original post

@dhikra-marghli8 

Take a look about the Token Bucket Algorithm

https://www.ccexpert.us/qos-implementing/example-token-bucket-as-a-piggy-bank.html

Best regards
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View solution in original post

11 Replies 11

Joseph W. Doherty
Hall of Fame
Hall of Fame

A shaper is a "tool" to limit bandwidth to some maximum allowance.  "Average" is a method used to how it calculates bandwidth consumption.

RSVP is an end-to-end methodology to guarantee some amount of bandwidth.

A shaper, or shapers, might be used, per hop, by RSVP, to accomplish its goals.

what are typical use cases for each feature:  ??

Hello

i wait more explain 

Thanks

A typical use case for using a shaper. . .

Suppose you have an ISP which provides a physical hand-off with much more bandwidth than you're allowed to use.  Common cases would be DSL, Fios, Cable, where you might only have a faction of the physical bandwidth as an allowance.  For example, you have a gig connection, but your bandwidth allowance is 200 Mbps.

Now what happens if you send 300 Mbps, on a gig connection, where your bandwidth allowance is 200 Mbps?

Generally, your ISP will drop 100 Mbps of your 300 Mbps.  But do you know when this happens?

What you might do, is place a 200 Mbps shaper on the gig interface.  Then you will see drops.  Further, you have the option to use QoS to determine what traffic will be dropped first.

As for common example of RSVP usage, I've never seen a real world implementation.

In theory, if your network application and network are configured to support RSVP, a possible good use case example would be you with to do a tele-meeting with some across the network.

So, what should happen, your tele-meeting network application requests the network to guarantee (reserve) the bandwidth it needs between the two tele-meeting network hosts.  All in-path network devices, need to participate and agree they can, and will, guarantee the bandwidth requested.  If any do not, the connection is not made.  But, if it is made, assuming your tele-meeting truly only needs the bandwidth it requested, it should operate flawlessly.

You might want to read this Cisco information; take note of RSVP in the IntServ model.

You might also find this Cisco TechNote helpful, as it explains a bit about how shaping, and its alternative policing, work.

I also recommend searching the Internet and/or Cisco sites, for (much) more (available) information on RSVP and/or shaping.

You also will likely find these Cisco forums most helpful when having a specific issue, like for shaping, perhaps, for example, how best to set Bc for a particular traffic type.  I.e. things not often found even with extensive Internet searches.

M02@rt37
VIP
VIP

Hello @dhikra-marghli8 

Traffic shaping is a mechanism used to control the rate of data transmission in a network. With "shape average," traffic is smoothed out over time to conform to a specified average rate. This means that bursts of traffic are limited, ensuring that the overall transmission rate remains within the configured average rate. Traffic shaping is commonly used to regulate the flow of traffic at the edge of a network, such as at a router interface connected to an ISP, to prevent congestion and ensure fair use of bandwidth.

RSVP is a signaling protocol used in computer networks to enable the reservation of network resources for specific data flows. With RSVP, devices along a data path can reserve bandwidth and other resources to ensure that sufficient capacity is available for the transmission of data. RSVP is commonly used in QoS implementations (IntServ) to prioritize certain types of traffic, such as real-time voice or video, and to guarantee quality of service requirements are met. Unlike traffic shaping, RSVP involves the explicit reservation of resources along the data path rather than smoothing out traffic over time.

 

Best regards
.ı|ı.ı|ı. If This Helps, Please Rate .ı|ı.ı|ı.

average shapping===> mean  it is the BC  ... if traffic > BC ==> that is mean this  this traffic remains in queue waiting

so my question ... if  this bandwidth  traffic > BC bandwidth===> wha'ts happen in the router ?

shapping average is configured in the CPE or PE backbone ?

I wait a reply for the two question 

 @dhikra-marghli8, let's clarify.

As concerned, average shaping and burst (Bc), when you configure average shaping, you are essentially specifying the average rate at which traffic is allowed to be sent. The Burst (Bc) is the amount of data that can be sent in a single burst at the specified rate. If the traffic rate exceeds the configured average rate (Bc), the excess traffic is typically buffered in a queue. This excess traffic will be sent out at a later time, adhering to the specified average rate.

Behavior When Traffic exceeds shaping rate ?
If the incoming traffic rate exceeds the configured shaping rate (Bc), the excess traffic is typically queued. The router will attempt to send the excess traffic later, according to the configured shaping parameters.

Typically, traffic shaping is configured on the egress interface of a router where the traffic needs to be shaped. This could be done at the customer premises equipment (CPE) or within the provider edge (PE) router in the backbone, depending on the network design.

 

Best regards
.ı|ı.ı|ı. If This Helps, Please Rate .ı|ı.ı|ı.


M02@rt37 wrote:

 @dhikra-marghli8, let's clarify.

As concerned, average shaping and burst (Bc), when you configure average shaping, you are essentially specifying the average rate at which traffic is allowed to be sent. The Burst (Bc) is the amount of data that can be sent in a single burst at the specified rate. If the traffic rate exceeds the configured average rate (Bc), the excess traffic is typically buffered in a queue. This excess traffic will be sent out at a later time, adhering to the specified average rate.

Behavior When Traffic exceeds shaping rate ?
If the incoming traffic rate exceeds the configured shaping rate (Bc), the excess traffic is typically queued. The router will attempt to send the excess traffic later, according to the configured shaping parameters.


BTW, although shaping and/or policing, describe rates, what is really done is management of "volume".  Physical links, even with shaping and/or policing, transmit at their line rate.

To make this clear, suppose you had a gig port which you shape to 500 Mbps.  Actual data is still always sent at gig.  However, during a selected time interval, only half (i.e. 500/1000 Gbps) the total bandwidth capacity of the port would be allowed to be transmitted.  So, the total data transmitted, for the selected time interval, would be the same as if the port was actually running at the specified rate.

This can be a bit of a subtle distinction, but it may have a real world impact.  For example, when doing QoS and supporting traffic prioritization for something like VoIP or video conferencing, often you want to use smaller time intervals, Tc (Tc = (Bc / CIR) x 1000).

@dhikra-marghli8 

Take a look about the Token Bucket Algorithm

https://www.ccexpert.us/qos-implementing/example-token-bucket-as-a-piggy-bank.html

Best regards
.ı|ı.ı|ı. If This Helps, Please Rate .ı|ı.ı|ı.

it is clear ...Thank you

you are the best expert


M02@rt37 wrote:

@dhikra-marghli8 

Take a look about the Token Bucket Algorithm

https://www.ccexpert.us/qos-implementing/example-token-bucket-as-a-piggy-bank.html


BTW, just be aware, the link's example deals with policing, but shaping attempt to queue the excess.

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