Aggregation router throughput

[Hamada Ahmed]

Hi,

I want to know how calculate my required throughput for aggregation router?

If my aggregation router will be in DC and will connect to 4000 Sites, each site use 10M as BW and this router has uplink 4X10G to LAN side in DC

So the required throughput, should be how much?

2- For LAN side , is it required be calculated ? for example these 4X10G uplinks need to consider? 

[balaji.bandi]

I calculate this way :

10MB per side x 4000 = 40,000MB (40Gig)  - so average usage will be not all the time 100% so that should be ok for 4X10GB

But that is your Lan side, but you did not mentioned how the WAN Side connection ? what Interface, what router is this ?

There is no hard rule, good to have additional bandwidth, either you need to look exiting utilisation past 6months calculate with that reference model when you design, if not moving forward you need to Monitor the links, and upgrade as required once it reached to 70-80% of load.

[Hamada Ahmed]

I want to buy new aggregation router DC, that why i need to know the required throughput

First :- we have 4000 sites (Branches) , each branch will access DC, so they will connect through WAN to aggregation router using IPSEC, each site has 10mb wan BW.

Second:- this aggregation router will connect to Core Switch in DC , with 4 uplinks, each one 10G, so i need to consider this Uplink BW in my calculation?

So i want to know the required throughput and how to calculate it?

[balaji.bandi]

Let me give you wise suggestion, this is very big requirement, do not go by community as design your network.

suggest to contact Local cisco partner and solution team to desing for you.

[Hamada Ahmed]

I just need example for calculation

Did i need to consider the LAN Uplinks and WAN

for example Calculation will be like below

10*4000 (WAN)+ 4*10 (LAN)= 80G total throughput?

am I right?

Also when should I need to consider LAN BW in my calculation and when not?

[balaji.bandi]

It all how your network connected and designed.

take example as below :

ALL(4000 connecting to WAN)   40GB WAN Side needted(Router)--40GB Lan side needed (wheren your DC network or Lan resource for the remote office to connect)

This in assumption you have 80% of the traffic, if you have 100% traffic consider 60GB WAN side 60GB Lan side.

[MHM Cisco World]

4000 ipsec, one ipsec for each branch ?

[Hamada Ahmed]

yes

but the issue now, how to calculate the required throughput ?

[Joseph W. Doherty]

Unless you size your router for maximum concurrent bandwidth, for all ports and sites, you need to "know" what your expected bandwidth usage is, for your clients.  Number of sites and/or number of hosts do not tell us that.  Going by what others have experienced may, or may not, be good for you.

Once you know your expected bandwidth needs, you can then "size" your router.

At this point, there's insufficient information for "us" to predict your bandwidth needs.

As others have suggested, assuming your existing (?) clients are representative on current and near term bandwidth needs, you can scale you solution based on that.  As also suggested by others, perhaps retaining a local network consultant would be able to help you.

[Hamada Ahmed]

I just need example for calculation

Did I need to consider the LAN Uplinks and WAN

for example Calculation will be like below " I have 400 sites, each site 10Mb BW, and this aggregation router will use 4 uplinks in DC, each 10G to core SW"

10*400 (WAN)+ 4*10 (LAN)= 44G total throughput?

am I right?

Also when should I need to consider LAN BW in my calculation and when not?

[Joseph W. Doherty]

"am I right?"

Possibly not.

If you only have 4 gig to WAN, then that's your bottle neck, you'll never use more than that bandwidth to/from DC.   I.e. One 10g link to DC can easily handle the 4 gig.

If this router is also routing on the LAN, it's possible your bottleneck would be the 40 gig.

If you could truly saturate both your WAN links and LAN links, concurrently (such as also passing WAN to WAN traffic via this router), then yes, you could get up to 44 gig, your total links bandwidth.

However, in the real-world, often you don't push all your links to full capacity, concurrently.  If you do, then you likely should have more bandwidth.

Although you can size a router for 44 gig, most likely you'll only need some fraction of that.  Unless you have an unlimited budget, normally you want to size a router for expected bandwidth usage demand with some room for growth.

When you start pricing out routers, you'll may "see", due to costs, why you want to size a router for true need, not for every port it supports running at 100% all the time.

[Hamada Ahmed]

Thanks for you clrafication,

and what if I have 4000 sites, each with 10Mb,

So it will be 10*4000 (WAN) + 4*10G (LAN) = 80G needed?

so this above calculation 

In case router handle routing in LAN side, I will need router with 80G?

and in case not handle routing in LAN side, only need 40G?

[Joseph W. Doherty]

For router capacity, and duplex links, you only need to sum up ingress, as one port's ingress will be another port's egress and forwarding is from ingress to egress.

So . . .

"So it will be 10*4000 (WAN) + 4*10G (LAN) = 80G needed?"

Assuming just WAN<>LAN, since WAN is the bottleneck, you need twice the WAN bandwidth for forwarding capacity, i.e. 8 Gbps.  (I.e. 4gig in from WAN with 4 gig in from LAN [more that 4 gig from LAN bottlenecks on 4 gig WAN egress ].)

Or if you only have LAN<>LAN, with the 4x10g, you would only need 40g of forwarding capacity.

[MHM Cisco World]

https://www.cisco.com/c/en/us/support/docs/routers/asr-1000-series-aggregation-services-routers/200674-Throughput-issues-on-ASR1000-Series-rout.html

don't depend on this for final decision, please contact Cisco for the more inf. but for now 
the throughout example in link and in photo explain how calculate the throughput BUT 
there is something else IPSec can do in HW where as you mention there are 4000 IPSec VPN.

https://www.cisco.com/c/en/us/products/collateral/routers/asr-1000-series-aggregation-services-routers/datasheet-c78-731632.html

please again contact Cisco for final decision.