BGP peering strategies for smaller routers

Tue May 3 13:20:16 UTC 2016

Mike wrote on 5/2/2016 9:43 PM:
> On 05/02/2016 07:35 PM, Eric Sabotta wrote:
>> Mike,
>>
>> I just did this with a ASR1001.  I had to upgrade it to 8gb of ram (I 
>> got the real Cisco stuff for ~ $500).  Before the router would crash 
>> when loading the tables.
>>
>> Right now, I have full tables from two providers:
>>
>> router1#show ip bgp summary
>> BGP router identifier 192.55.82.2, local AS number 4505
>> BGP table version is 11150622, main routing table version 11150622
>> 582461 network entries using 144450328 bytes of memory
>> 911730 path entries using 109407600 bytes of memory
>> 148924/93298 BGP path/bestpath attribute entries using 36933152 bytes 
>> of memory
>> 132977 BGP AS-PATH entries using 6043938 bytes of memory
>> 0 BGP route-map cache entries using 0 bytes of memory
>> 0 BGP filter-list cache entries using 0 bytes of memory
>> BGP using 296835018 total bytes of memory
>> BGP activity 962568/380103 prefixes, 5155645/4243915 paths, scan 
>> interval 60 secs
>>
>> Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ 
>> Up/Down  State/PfxRcd
>> 192.55.82.3     4         4505 2532914 1634867 11150622    0 0 
>> 3w0d       330377
>> 192.55.82.4     4         4505  672950 1634865 11150622    0 0 
>> 3w0d            1
>> 209.117.103.33  4         2828 1837130   48052 11150557    0 0 
>> 2w1d       581351
>>
>> router1#show ip cef summary
>> IPv4 CEF is enabled for distributed and running
>> VRF Default
>>   582527 prefixes (582527/0 fwd/non-fwd)
>>   Table id 0x0
>>   Database epoch:        2 (582527 entries at this epoch)
>>
>> -Eric
>>
>
> But if I'm reading the above right, it looks like bgp is eating ~300mb 
> on your box.
>
> BGP using 296835018 total bytes of memory
>
> You would seem to have plenty of free ram. In my case, the ASR1002 
> doesn't have upgradable memory anyways so I'm stuck.
>
> Mike-
>
>
Mike, I have a customer that has not had any operational issues taking 
two full IP4 feeds on an ASR1002 with RP1 @ 4GB of RAM. Again, I'd 
recommend an ESP10 to ensure you have enough TCAM to hold the FIB and to 
track netflow or other data that relies on the ESP. I can't comment on 
the RP2's memory usage or stability as I don't think I've ran into them.

Here's the output to show you what to expect:

#sh processes memory | inc BGP|Total:|PID
Processor Pool Total: 1725514176 Used:  918478524 Free:  807035652
  lsmpi_io Pool Total:    6295088 Used:    6294116 Free:        972
  PID TTY  Allocated      Freed    Holding    Getbufs    Retbufs Process
  114   0        252          0      23264          4          4 BGP 
Scheduler
  282   0     165948     327892     189212          0          0 BGP Task
  294   0          0          0      17264          0          0 BGP HA SSO
  317   0  610260780          0     220080    3387715    3387715 BGP I/O
  355   0          0   17841472      23264          0          0 BGP 
Scanner
  405   0          0          0      23316          0          0 BGP 
Consistency
  422   0          0          0      23264          0          0 BGP Event
  528   0  560439808  646907016  498109200         51         51 BGP Router
  533   0          0          0      17264          0          0 BGP VA

#sh bgp su
BGP router identifier 1.2.3.4, local AS number ccccc
BGP table version is 66249122, main routing table version 66249122
598594 network entries using 86197536 bytes of memory
1177526 path entries using 94202080 bytes of memory
208207/100401 BGP path/bestpath attribute entries using 28316152 bytes 
of memory
179429 BGP AS-PATH entries using 7090834 bytes of memory
4342 BGP community entries using 230370 bytes of memory
1 BGP extended community entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 216036996 total bytes of memory
BGP activity 2943907/2345309 prefixes, 10963622/9786096 paths, scan 
interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ 
Up/Down  State/PfxRcd
a.a.a.a 4          aaa 5523968   51273 66249070    0    0 4w4d 578933
b.b.b.b 4        bbbbb 3731440  101400 66249070    0    0 4w4d 598586

#sh cef fib
599851 allocated IPv4 entries, 0 failed allocations
1 allocated IPv6 entry, 0 failed allocations

#sh ip route summary
IP routing table name is default (0x0)
IP routing table maximum-paths is 32
Route Source    Networks    Subnets     Replicates  Overhead Memory (bytes)
connected       0           60          0           3600 10800
static          20          79          0           6060 17820
bgp ccccc       180614      417599      0           35892780 107678340
   External: 598213 Internal: 0 Local: 0
internal        6552 23993840
Total           187186      417738      0           35902440 131700800