02-08-2016 09:50 PM - edited 03-05-2019 03:18 AM
Hello dear experts.
We are planning backbone network around 6 core router and 40 aggregation router. We plan to migrate 400K user to this network. Each user max speed is 20Mb. My question is that: is there have any formula to calculate the required bandwidth for backbone interconnections and especially for uplinks to support all user traffic? I know its impossible. But anyway i waiting for your valuable feedback.
Many thanks.
Solved! Go to Solution.
02-09-2016 01:13 AM
Hello Sefail,
400K users = 400000 users
6 core routers and 40 aggregation routers.
You will have 10000 users per aggregation router.
Allowing 20 Mbps per user would mean 20 Mbps * 10000 to the core from each aggregation router = 200 Gbps.
Now, accepting some overbooking like a factor 5:1 you finish to have 200/5 40 Gbps from each aggregation node to the core node(s).
40 aggregation routers connected to 6 core routers to two different core nodes means:
40/6 * 2 roughly 14 x 20 Gbps = 28 Ten Gigabit port just to connect the aggregation nodes per core node.
We have to add the links between core nodes now.
Le's suppose again that 20% of the traffic received from the downstream aggreg. nodes is destined to some destination attached to another core node.
You would need 20% of 28 TenGiga to reach the other core nodes, 6 Tengiga to each of the other core. Your core routers needs to support 30+28 = 58 Tengigabit ports.
Hope to help
Giuseppe
02-09-2016 01:13 AM
Hello Sefail,
400K users = 400000 users
6 core routers and 40 aggregation routers.
You will have 10000 users per aggregation router.
Allowing 20 Mbps per user would mean 20 Mbps * 10000 to the core from each aggregation router = 200 Gbps.
Now, accepting some overbooking like a factor 5:1 you finish to have 200/5 40 Gbps from each aggregation node to the core node(s).
40 aggregation routers connected to 6 core routers to two different core nodes means:
40/6 * 2 roughly 14 x 20 Gbps = 28 Ten Gigabit port just to connect the aggregation nodes per core node.
We have to add the links between core nodes now.
Le's suppose again that 20% of the traffic received from the downstream aggreg. nodes is destined to some destination attached to another core node.
You would need 20% of 28 TenGiga to reach the other core nodes, 6 Tengiga to each of the other core. Your core routers needs to support 30+28 = 58 Tengigabit ports.
Hope to help
Giuseppe
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