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Suggestion for BNG

puddingtech
Level 1
Level 1

I'm looking for recommendations on converging my network into a single BNG, we have multiple access networks, wireless, gpon, dsl etc... and we want to trunk them all back over L2 and terminate on a BNG...

Clients will be ~2000 growing most likely to the 8000-10000 range down the road, and ~2 gigs scaling to estimated 20 gigs once we start rolling out gpon and vdsl... So the networks we will be moving are quite small now but theirs a lot of growth on the nearterm expected that i need to be able to deal with.

Would like the new network to be DHCP (IPoE) using unnumbered addresses... as we want to move away from the existing mix of Static IP (OSPF) and PPPoE customers...

Ability to have HA, and moving to a Dual Stack environment when we decide to are also concerns

I've been eyeing the ASR9001 and the ASR1K lines, not sure which way to go to handle what we have but scale to where we expect to be and beyond... Not to mention the large number of options on both product lines...

 

1 Accepted Solution

Accepted Solutions

xthuijs
Cisco Employee
Cisco Employee

For BNG you probably want to look at the XR based solution longer term. Eventhough its scale is higher then what you need, the good thing is that it is license based so you can start low, and have the ability to scale up by adding some lics.

eg take the 9001-S, which gives you 2 onboard 10GE's and an MPA bay, one NPU, so 32k subs max up to 60G bps.

you can take a lic for 8k subs, and increase as you need. and as you need more bw you can up the lic for the 9001-S to the 9001 and get both MPA's and all 4 10G's enabled.

Our longer term BNG strategy focuses on the XR.

regards

xander
 

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6 Replies 6

xthuijs
Cisco Employee
Cisco Employee

For BNG you probably want to look at the XR based solution longer term. Eventhough its scale is higher then what you need, the good thing is that it is license based so you can start low, and have the ability to scale up by adding some lics.

eg take the 9001-S, which gives you 2 onboard 10GE's and an MPA bay, one NPU, so 32k subs max up to 60G bps.

you can take a lic for 8k subs, and increase as you need. and as you need more bw you can up the lic for the 9001-S to the 9001 and get both MPA's and all 4 10G's enabled.

Our longer term BNG strategy focuses on the XR.

regards

xander
 

Great recommendation, definitely will look into the -S to start out with from my initial checks its a huge savings.

Though the 01's are non hardware redundant, do you have any advise how one would run 2 of them parallel for redundancy in the event of a hardware failure. In our new network layout we're trying to remove any single points of failure. Would be great if you knew of how... We'll be picking up smartnet with the units if we go with the 9k1-S so i'm sure they could help post-sale but then again kinda helpful to know what i'm getting myself into by not going with a more expensive chassis setup.

Thanks again

chris

 

hi chris, you have 3 options here:

cluster (requires license) and bundle 2 separate chassis together as one logical system

geo redundancy (requires license) makes 2 devices sync subs between devices

cold standby, basically 2 devices sharing a subnet/vlan and a pppoe session will send its padi to both devices and only one will connect the sub, if the device fails, the session will reinitiate and connect with the other.

cheers!

xander

Well 3rd option isnt possible as we're going DHCP route not PPPoE.

 

Clustering looks solid but leaves only 1x10g port for data traffic on each 9001-s but thats actually not bad considering size of our network. Was actually getting excited until i checked the price of the nvcluster license.. Wow it literally doubles the cost of each router from the pricing i've seen online.

 

Geo redundancy looks like it will handle things they even mention dhcp initiated sessions in the 9k manual, i'll look around and see if i can track down the pricing. 

 

Thanks again

hey chris, even for dhcp the 3rd option could work. the discover is sent to both devices and then the client will select only one offer.

the nasty part about this is only that this is somewhat dependent on the lease timer of dhcp because both nodes obviously need to be on different pools/subnets for the subs.

now you could add a packet trigger so that clients who had a lease can continue their session on the mated pair (somewhat of an ss7 term I guess), and after lease expiration they will rediscover to the other bng node and get a new address.

cheers!

xander
 

Ya i figured about that much, but thats a pretty nasty way to make it work :) I've been looking but i don't see the licenses for the 9k1 Geo Redundancy anywhere, i see the Nv licenses but nothing about geo redundancy even in the manual it doesn't mention the license