[j-nsp] NETCONF vs SNMP for monitoring

[Phil Mayers]

On 30/08/14 17:30, Tyler Christiansen wrote:
> SNMP is less resource-intensive and faster than NETCONF.  I would use SNMP
> for the things you can and NETCONF for the things you can't.  If you

I would agree with this, based on our extensive playing. We tend to 
monitor with SNMP, configure with Netconf/Junoscript.

Couple of additional points:

  1. Sometimes the SNMP MIB is really horribly organised either from a 
performance point of view ("OIDs shall be ordered by prime factorial of 
birth date" - hateful if you need to fetch a whole table of 10k rows to 
get one item) or needing to fetch a jillion separate tables to get the 
final result. In this case, Netconf *may* be faster but...

  2. ...you need to account for the overhead of setup/teardown of the 
Netconf session, particularly the SSH/HTTPS key exchange. On low-end 
devices (EX3300) the CPU were sluggish enough that we opted for plain 
TCP transport Junoscript, relying on the firewalled management VLAN for 
security. Try to catch everything in one Netconf session - Tyler's point 
about async/threading is very relevant here.

  3. Occasionally you'll find things not exposed over SNMP; obviously 
then Netconf

  4. Finally, you may find that bulk data collection - e.g. all the 
counters, all the ARP / ethernet switching table entries - is quicker 
over Netconf. SNMP results need to be OID-sorted which can be slow, but 
also the TCP transport can end up being faster than UDP. Test and see 
which works, but also beware faster collection may mean higher CPU on 
the monitored device.