[c-nsp] ASR-100x intro

Lukasz Bromirski lukasz at bromirski.net
Sat Feb 16 13:29:13 EST 2013

On Feb 16, 2013, at 10:34 AM, Charles Sprickman <spork at bway.net> wrote:

> On Feb 8, 2013, at 12:27 PM, Mack McBride wrote:
>> One of the questions I haven't gotten a good answer to.
>> The ESP actually has the hardware for the route table.
>> The ESP20 and ESP40 handle 4 million routes.
>> The others handle less (the 5G for examples handles 500k v4 or 125k v6).
> And the ASR-1002-X with the "integrated" ESP-?? handles "1M IPv4 or 1M IPv6 routes" according to http://www.cisco.com/en/US/prod/collateral/routers/ps9343/data_sheet_c78-450070.html
> But the ESP-20 and ESP-40, which share many specs with the mystery embedded ESP in the 1002-X claims "4M IPv4 or 4M IPv6".
> I don't know what the "OR" means, I can have 1M v4 OR 1M v6 but not some mix of the two?  The use of the word "or" there is strange.

It's either 1M for IPv4, 1M for IPv6 or some mix of it, depending on your requirements.

> And the RP side is clear as mud as well.  The RP2 also claims "4M IPv4 or 4M IPv6" with the 16GB RAM option, but then the 1002-X "embedded" RP2 is back at the "1M IPv4 or 1M IPv6" number even though it's possible to order the 1002-X with 16GB RAM.

For the RR role (when the entries are not downloaded to FIB) it'll be around 22-24M depending
on the config and the requirements with 16GB of RAM.

> Am I understanding the architecture of this correctly?  I mean, if my RP2 can hold 4M routes, which today would be what, about 9 full views, are ALL those routes shoved down to the forwarding plane, or just the "best" routes?  If so, why can't a lesser-spec'd ESP be limited to 1M routes even if the RP2 has 4M "possible" paths?

Only best entries are programmed into FIB (unless you enable BGP PIC, or additional-paths
extensions). That's for typical usage. For RR, you use table-map to stop programming
entries into FIB (typical for RR scenario), and you can max-out the RAM with the

>> What happens to the other routes?
> Maybe we're asking the same question.  I hope so.

They fail to fit into available RAM, and process responsible for 'getting them' will

>> It seems they could get handled in software but the ESP is basically software anyway.
>> So the situation is clearly opaque.
> The 1002-X makes it even more opaque.  Someone said earlier in the thread that the 1002-X is essentially a fixed-config with an RP2 and an ESP-40.  But the specs don't match, at least on the number of routes.

They should, it's a question of what's supported today and what will be supported.
For example, because of the way the ESP and RP are connected, and the front-facing
ports, it's rated at 36Gbit/s maximum - while it's still ESP40.

QuantumFlow is a matrix of CPUs - in this sense it's a "software", but given the way
those work, how the tasks are programmed and processed on them it's treated as
'hardware forwarding'.

>> The MX80 from juniper for example has the same situation and is equally opaque.
> We've had some very rough times getting similar information on the Juniper MX series.  There is some hint that the RP equivalent can have more routes than the FIB, but nothing definite and no hard numbers so far after putting in multiple requests with our Juniper salesperson.  We're also getting mixed answers about whether the integrated GigE ports on the MX are capable of hierarchical queueing when the chassis is fully "unlocked" as an MX-80 (this sounds incorrect based on what I've read, but some SE over there is claiming that's the case).

>From the practical experience, they're not. But you can also check it
out in the official Juniper docs:


> All I really want to know is if 3-5 years down the line, assuming these graphs (http://bgp.potaroo.net/v6/v6rpt.html) are still ramping up and we are looking at 4-5 full views of v4 and v6 will I be needing to retire the damn thing.  Traffic-wise, both boxes are fine for that long.  I also suspect (at least in the cisco case with the RP2) there is enough cpu power to last quite some time.
> This is almost making going with a used 6500 bundle look appealing.

If you have doubts, look at ASR9001. 

"There's no sense in being precise when |               Łukasz Bromirski
 you don't know what you're talking     |      jid:lbromirski at jabber.org
 about."               John von Neumann |    http://lukasz.bromirski.net

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