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Cisco Employee
Cisco Employee



In this document we'll be discussing the SNMP architecture as it is implemented in IOS-XR. As you can read in the IOS to XR migration guide (A starting point), some of the high level differences between IOS and XR are already being highlighted.

As IOS-XR is a highly distributed operating system and is using hardware forwarding, the way that SNMP retrieves counts and responds to requests is a bit different then what you might be used to and in this article we deep dive into the architecture of stats collection, how it operates and what show commands you can use to verify the performance of your SNMP in regards to IOS-XR and specifically for the ASR9000 (though this article also applies to CRS and GSR running IOS-XR).

XR routers are highly distributed. Increasing capacity by distribution and replication does come at a cost. In any scaled design where replication or multiplication of the processing devices is used, a critical additional component is the design is the inter process communication path between the processing components


The nature for this article originated from the fact that some of our customers have seen SNMP timeouts in XR 4.2.3 and has raised a lot of questions in regards to caching, stats collection and the way SNMP operates. Hopefully with this technote we can clear up some of the confusion.


SNMP architecture in IOS-XR

This section describes the symptoms of the problem and the main issue the document resolves.


SNMP Packet flow inside the system

Depending on your configuration SNMP packets can be received in band or out of band (as per MPP definitions, see article on LPTS and MPP for more info) and after intial reception and punting to the control plane (RSP), they are handed over to NETIO. NETIO is sort of an IP INPUT process in IOS that deals with process level switching.

IF the SNMP requests are "for me" they are handed over to the SNMP-D process for evaluation of the request and dispatch to the next layer of processing.


Screen Shot 2013-03-25 at 1.36.54 PM.png

XR SNMP Specifics


  • Informs supported as of 4.1 (Inform proxy not supported)
  • Full AES Encryption support in 4.1 (V3 related)
  • Full IPv6 support  In 4.2 (snmp engine transport)
  • VRF-aware support in 3.3  (snmp engine, some MIBs already available)
  • Across Cisco capability files not well supprtoed, ASR9K MIB guide developed to improve situation
  • Event/expression MIB support for extendibility as in IOS
  • Warm standby on snmp agent
  • Management plane protection (mpp) / snmp overload control to limit impact of snmp on device
  • Standards based MIB support (IETF & IEEE)



IP MIBs support

Routing MIBs support (BGP, OSPF, ISIS, etc)

MPLS, Pseudowire, VPLS MIBs support



SNMP performance improvements

  • Asynchronous request processing / multithreading (4.2)
  • Bulk processing (dedicated processing path for bulking) (4.2)
  • Data Collection Manager – bulk MIB data collection and file push (4.2.0 & 4.2.1)
  • Additional IPv6 / VRF aware MIB support (4.2 and after)
  • Additional improvements with Async IPC and SysDB Backend infra (4.1)
  • Overload Control Integration (4.0)

SNMP request processing blocked during critical event periods (i.e. OSPF convergence)


  • Additional PDU performance monitoring support (4.2)
  • MIB guide update (4.2)



Caching is an integral part of IOS XR SNMP processing allowing it to perform at best performance while maintaining the most accurate stats possible.

There are various levels of caching and some of them are configurable, some of them are not. The reason why we cache is also to alleviate the hardware from the burden of getting continuous requests, especially in WALK scenarios retrieving many requests for eg interface stats counters.


There is a process called STATS-D which is a proc running on the linecard that periodically scrapes statistics of the linecards hardware and updates the interface counters and MIB stats.

This means that if you poll within the stats-D update time, you'd realistically see the same counter being returned twice.

Show interface commands (depending on release) will force a direct update read from hardware to get the most accurate reading, but the IF-MIB stats are cached.

Screen Shot 2013-03-25 at 1.23.01 PM.png


1.The SNMP UDP transport receives sends a SNMP GetRequest-PDU, GetNextRequest-PDU or GetBulk-PDU to the SNMPD.
2.The SNMP Engine parses the PDU and dispatches the individual variable bindings. IF-MIB objects are dispatched to mibd_interface process & IF-MIB DLL callbacks get invoked.
3.If the request is a getnext, the IF-MIB’s cache of variable bindings is checked to see if there is a cache hit. If so, the value is returned to the engine and the response PDU is sent. ***look-ahead cache


4.If no cache hit, the IF-MIB passes a message to the statsd_manager process to get the information for the interface (and the next 99 interfaces for the cache in the getnext case). IPC = LWM The sysdb direct EDM connection invokes the EDM for statsd.
5.The statsd_manager gets the interface data from its cache and returns the statsd bags for the interfaces to IF-MIB.


Visualizing caching differently:


Screen Shot 2013-03-25 at 1.30.28 PM.png


Two caching mechanisms:

  1. Statsd caching
  2. Lookahead caching

1: Statsd caching:

Used for interface related statistics (IF-MIB, IF-EXTENSON-MIB, etc.)

Statsd caching is configurable (via CLI).

2: Lookahead caching:

Conceptually a varbind cache.

Not configurable.

Not all MIBs leverage/use this cache.

Statsd cache:

– Use command “snmp-server ifmib stats cache”* to enable it.
– This is a periodic cache which gets refreshed every 30 seconds for all interfaces.
– Statsd cache maintenance is done irrespective of this command. The command only dictates from where to fetch the stats.
– Without the above command stats are actually fetched from the linecard, real-time counters. (Default behavior).
• Involves more number of processes and hence more CPU utilization and latency. Additional tax for real-time counters.


System maintains look ahead cache:

– Stats fetched for next 100 rows (interfaces) in bulk and cached.

***Data for up to 500 interfaces kept in cache 

– Cache is maintained for a max of 20 seconds.
– Oldest used blocked is reused to maintain a new set of cache.
– There is no **** to enable/disable this cache.
– Provides good performance improvement if used along with statsd cache.


Parallel vs Serialized processing

The following picture tries to explain what the serialized processing means:

When an SNMP request is being received they are handled in a sequential manner. If one request currently in progress is "slow", subsequent requests are waiting to be handled and may time out.

The NMS station may resend its SNMP request building up the request queue potentially causing more trouble.

Now the good news is in 431 we have the ability to detect duplicate requests and throw them out of the queue making sure we're dealing only with "NEW" requests.


Screen Shot 2013-03-25 at 12.59.33 PM.png


Enhancements in XR 4.1


Screen Shot 2013-03-25 at 1.15.33 PM.png


Enhancements in XR 4.2


Screen Shot 2013-03-25 at 1.15.42 PM.png


Example (performance) trace point logging


Screen Shot 2013-03-25 at 1.15.58 PM.png



SNMP process architecture

  • All management interfaces (SNMP, XML, CLI) utilize the same core processing architecture [sysdb].
  • The SNMP processing architecture serializes PDU processing (pre-4.2).
  • Request PDUs for all pollers effect the response rate seen for a single poller.
  • The SNMP per-OID polling rate is very MIB specific (each MIB’s underlying data model dictates the performance of MIB’s OID access)
  • MIB request processing commonly involves the GSP IPC mechanism, sysDB (data store) and statsd in some cases.
  • In band and out of band SNMP requests are treated the same within SNMP.
  •      (In band means that the SNMP request can be received on an interface that is also transporting customer/user traffic. Out of band interfaces, such as the MGMT interfaces on the RSP are dedicated for management and carry management traffic only).
  • The current SNMP architecture has an SNMP daemon enqueue requests and separate MIB daemons process requests (requests are enqueued from transport layer receive fairly quickly)
  • There are multiple MIB-specific caching mechanisms in place to improve performance which also complicate the polling rate calculations.
  • There is no queue size limit for SNMP requests (grows with memory).


XR processes referenced


StatsD is a process that collects statistics from various places (eg hardware) and updates tables on the LC shared memory.

IPC is an inter process call or communication that is used by processes to talk to each other to request data or send commands.

GSP is group services protocol, which is a process in IOS-XR that allows for one process to communicate with multiple "nodes" at the same time (like a sort of multicast way that the RSP can use to talk to multiple linecards, for instance to update a FIB route).



SNMP tracepoints


“show snmp trace requests” is a sliding window of logs indicating the above information about PDU processing


Screen Shot 2013-03-25 at 1.06.58 PM.png


XR MIB implementation specifics

Implementations of specific MIBs packaged as individual DLLs. Each MIBd process “houses” a group of MIB DLLs
Grouped according to the “type” of MIB—interface, entity, route, infra, at runtime, grouping is determined via a config file in XR source control
MIB DLLs handle the specifics of mapping MIB defined data model to XR data model. MIB DLLs map MIB namespace to XR data owner access
APIs (sysdb EDM is most common)
Look-ahead Caching—Any support for look-ahead cacheing is done within the MIB DLL. (No generic support for all MIBs)
Non-look-ahead cacheing—Some features may support access to cached managed data. These are accessed via separate data access point (ie. separate sysdb EDM path)


Screen Shot 2013-03-25 at 3.01.03 PM.png

Troubleshooting commands and what they do


The following show and debug commands are very powerful to verify and track SNMP.


show snmp

Global agent counters—incoming,   outgoing (request and trap), & error PDUs


- Periodically collect output to determine overall PDU response rate and identify error rate.

show snmp   trace requests

Log of   high level PDU   processing tracepoints—Rx, Proc Start, Tx   time


Periodically collect this log. Decode and use the data to determine the   following per-PDU   data:

1.Source   IPs of   pollers
2.Queue   lengths of per-source IP PDU queues
3.Types   of request PDUs   being used
4.Timestamp   when PDUs   are enqueued   into the queues for the source IPs
5.Duration   of the PDU enqueued   & waiting to be processed
6.Processing   time of PDUs   from pollers

show snmp mib   access

Per-OID   counters indicating the number of times an operation was done on that OID, ie.   GET, GETN,   SET.


Periodically collecting & diff will   indicate what was polled during the time periods.

show snmp mib   access time


Per-OID timestamp of the last operation on the OID.


Periodically collecting &   diff will indicate if any polling on the OID   was done in the time period.

debug snmp   request


Enable   to log every OID   being processed by every PDU to syslog.   Need to enable “debug snmp packet” as well to identify source of PDUs.

NOTE: Disable “logging trap debug” if “snmp trap syslog” is configured!!!

debug snmp   packet


Enable to log same data as “sh snmp   trace requests” to syslog.

NOTE: Disable “logging trap debug” if “snmp trap syslog” is configured!!!



Show commands that are new to XR 4.2 onwards


show snmp mib   statistics

Per-OID statistics summarizing   transaction times within the mibd level—count + min/max/avg .


Collect to determine if specific MIB   objects are averaging high processing times and/or large variance (low min,   high avg & max).

show snmp   queue rx

Indicates   the min/max/avg   queue sizes for the PDU receive and pending queues. Real-time and 5min views.

show snmp   queue trap

Indicates the min/max/avg queue sizes for the internal trap PDU   queue

(config)# snmp   logging thresh oid

show snmp   trace slow oid

Allows   configuring a duration threshold for logging per-OID transactions exceeding   the time threshold.

This   is measured within the mibd process beginning with the call to the   MIB specific handler for the OID and ending with the response from the same.

(config)# snmp   logging thresh pdu

show snmp   trace slow pdu


Allows   configuring a duration threshold for logging per-PDU transactions exceeding   the time threshold. When logging all   OIDs within the PDU are also logged to this buffer.

This   is measured within the snmpd process beginning with the dequeue   of the PDU from the receive queue and ending when all the OIDs in the PDU   have been processed and the response is ready to be sent.


Troubleshooting PDU performance issues


Some MIBs dont have accelerated processing or dont have caching and because in certain releases SNMP is processed serially, it could happen that you'll see timeouts on OID requests that are normally operating perfectly fine. An example of a slow MIB is the SONET MIB. Because this mib needs to talk from the SNMP process all the way down to the SPA of the SIP-700 linecard (on the ASR9000), the response may not be provided in a timely manner. At the same time new requests for other OID's may be in the holding or pending queue causing timeouts and retries.

Retries to an already under performing MIB may exacerbate the overal issue.


The vast majority of PDU performance issues are related to a poller polling a specific MIB which is slow to process its OIDs.

This causes all other pollers to see some of their PDUs slowed due to queueing delays (waiting on slow MIB)

Troubleshooting Goal:

     Identify the slow MIB/MIBs being polled


Use SNMP View Access Control to block access to the slow MIB tables / objects

snmp-server view MyPollView <slow MIB OID> excluded

Use ACLs to permit only “known” NMS devices/applications . In this case “known” is referring to content of requests issued from the app



Determining Internal Timeout of a MIBd

snmpd will timeout a mibd process if it has not received a response to a request for an OID/s within 10s by default.

Once in timeout state, snmpd will continue processing requests BUT it will mark the mibd as unavailable until it responds to the timed-out request.


  • Getnext operations to any OIDs for MIBs in the timed out mibd will skip to the lexi-next OID owned by a different mibd process.
  • Get/Set operations to any OIDs for MIBs in the timed out mibd will be responded to with a PDU error-code of “resourceUnavailable”.


(in addition to normal “slow OID” techniques):

If able to catch mibd in the state:
run attach_process –p <PID of mibd process> -i 5 –S
May be possible to identify the MIB being polled via examining “show snmp lib group agent ipc” for “request timeout” to get the timestamp for when
the mibd timeout is detected.
Using the timeout timestamp, “sh snmp mib access time” may still have an OID timestamp correlating to 10s prior.


Examples and Recommendations

For the purpose of clarification the following is an example of an snmp table. The columns (vertical) represent the instance or entity, and the rows represent the objects. In this case we have 3 instances 1, 2 and 3, and each instance has 3 objects, ifName, ifInOctets and ifMtu.





















The customers current snmp design is using snmpwalk. Snmpwalk works by performing a sequence of get-nexts, but on a column by column  basis if the column object is specified as the starting point.


An example of a column walk specifying the ifDescr from IF-MIB

[no-sense-1 68] ~ > snmpwalk -c public   IF-MIB::ifDescr

IF-MIB::ifDescr.1 = STRING: Loopback0

IF-MIB::ifDescr.2 = STRING: Bundle-POS1

IF-MIB::ifDescr.3 = STRING: Bundle-Ether1

IF-MIB::ifDescr.4 = STRING: TenGigE1/2/0/0

IF-MIB::ifDescr.5 = STRING: TenGigE1/2/0/1

IF-MIB::ifDescr.6 = STRING: SONET0/2/0/0

IF-MIB::ifDescr.7 = STRING: SONET0/2/0/1

IF-MIB::ifDescr.8 = STRING: SONET0/2/0/2

IF-MIB::ifDescr.9 = STRING: SONET0/2/0/3

IF-MIB::ifDescr.10 = STRING: SONET0/2/0/4



Snmpwalk can also be used to get a single object only, for instance, the object IF-MIB::ifDescr.9. It does not support the ability to specify any more than 1 object in its request. The example below shows two objects being requested, but only the first returned.


[no-sense-1 69] ~ > snmpwalk -c public IF-MIB::ifDescr.9

IF-MIB::ifDescr.9 = STRING: SONET0/2/0/3

[12:18 - 0.31]


[no-sense-1 70] ~ > snmpwalk -c public IF-MIB::ifDescr.9 IF-MIB::ifDescr.10

IF-MIB::ifDescr.9 = STRING: SONET0/2/0/3

[12:18 - 0.36]


For efficiency row traversal is preferred, with multiple objects requested in a single snmp transaction. This reduces unnecessary overhead on the XR system. For this reason snmpwalk is not recommended.



Examples of row traversal

The customer is currently requesting via snmpwalk the following IF-MIB objects














The preferred method is to specify all the objects required from an instance/entity in a single command such as get-next or bulk-get. An example follows using snmpbulkget



[no-sense-1 115] ~ > snmpbulkget -v 2c -c public IF-MIB::ifDescr IF-MIB::ifHCInOctets IF-MIB::ifHCOutOctets IF-MIB::ifHCInUcastPkts IF-MIB::ifHCOutUcastPkts IF-MIB::ifInNUcastPkts IF-MIB::ifOutNUcastPkts IF-MIB::ifInOctets IF-MIB::ifOutOctets IF-MIB::ifInUcastPkts IF-MIB::ifOutUcastPkts

IF-MIB::ifDescr.1 = STRING: Loopback0

IF-MIB::ifHCInOctets.2 = Counter64: 0

IF-MIB::ifHCOutOctets.2 = Counter64: 7116596

IF-MIB::ifHCInUcastPkts.2 = Counter64: 0

IF-MIB::ifHCOutUcastPkts.2 = Counter64: 99611

IF-MIB::ifInDiscards.2 = Counter32: 0

IF-MIB::ifOutDiscards.2 = Counter32: 0

IF-MIB::ifInOctets.2 = Counter32: 0

IF-MIB::ifOutOctets.2 = Counter32: 7116596

IF-MIB::ifInUcastPkts.2 = Counter32: 0

IF-MIB::ifOutUcastPkts.2 = Counter32: 99611

IF-MIB::ifDescr.2 = STRING: Bundle-POS1

IF-MIB::ifHCInOctets.3 = Counter64: 38796828

IF-MIB::ifHCOutOctets.3 = Counter64: 66076323

IF-MIB::ifHCInUcastPkts.3 = Counter64: 331833

IF-MIB::ifHCOutUcastPkts.3 = Counter64: 402546

IF-MIB::ifInDiscards.3 = Counter32: 0

IF-MIB::ifOutDiscards.3 = Counter32: 0

IF-MIB::ifInOctets.3 = Counter32: 38796828

IF-MIB::ifOutOctets.3 = Counter32: 66076323

IF-MIB::ifInUcastPkts.3 = Counter32: 331833

IF-MIB::ifOutUcastPkts.3 = Counter32: 402546

IF-MIB::ifDescr.3 = STRING: Bundle-Ether1



Note above that all the objects in a row for all instances (columns) are obtained with one command. The same can be done with a get-next, however the added overhead of including the instance must be used for each instance present.


[no-sense-1 120] ~ > snmpgetnext -v 2c -c public IF-MIB::ifDescr.1 IF-MIB::ifHCInOctets.1 IF-MIB::ifHCOutOctets.1 IF-MIB::ifHCInUcastPkts.1 IF-MIB::ifHCOutUcastPkts.1 IF-MIB::ifInNUcastPkts.1 IF-MIB::ifInOctets.1 IF-MIB::ifOutOctets.1 IF-MIB::ifInUcastPkts.1 IF-MIB::ifOutUcastPkts.1


IF-MIB::ifDescr.2 = STRING: Bundle-POS1

IF-MIB::ifHCInOctets.2 = Counter64: 0

IF-MIB::ifHCOutOctets.2 = Counter64: 7116596

IF-MIB::ifHCInUcastPkts.2 = Counter64: 0

IF-MIB::ifHCOutUcastPkts.2 = Counter64: 99611

IF-MIB::ifInDiscards.2 = Counter32: 0

IF-MIB::ifInOctets.2 = Counter32: 0

IF-MIB::ifOutOctets.2 = Counter32: 7116596

IF-MIB::ifInUcastPkts.2 = Counter32: 0

IF-MIB::ifOutUcastPkts.2 = Counter32: 99611

[13:03 - 0.35]


Although the examples are specific to IF-MIB, the same concept is relevant to all MIBs.


Timeout and Retry Setting on NMS

Timeout recommenations:

  1. use dynamic timeout when available
  2. if dynamic timeout is not available, increase timeout if more management applications are simultaneously polling the SNMP agent on asr9k. Multiply the default timeout by the number of applications that are simultaneously polling the SNMP agent on asr9k.


Retry recommendations:

  1. use dynamic retry when available
  2. if dynamic retry is not available, establish number of retries based on testing


For more details refer to IOS XR SNMP Best Practices.



Special thanks to the XR SNMP dev team for some of the amazing content used in this article, most notably Timothy Swanson and Leon Zachary




Xander Thuijs CCIE #6775

Principal Engineer, ASR9000

Cisco Employee
Cisco Employee

Hi Abraham,


There's a lot to monitor, some guidance in the below links. Basically you should first decide what is important for you to monitor (a healthy system and services) then translate that to OIDs.


Implementing SNMP on Cisco IOS XR Software


SNMP Server Commands on Cisco IOS XR Software


SNMP Object Navigator:


MIB Guide:


General guide to supported MIBs:


Specific MIBs for 4.2.0:


CISCO-PROCESS-MIB information:


Collecting CPU utilisation on Cisco IOS devices using SNMP:


Determining free and the largest block of contiguous memory usage on Cisco IOS devices with SNMP:


Performance Monitoring feature offers CPU, memory, bgp, ldp and interface monitoring:



Cisco Employee
Cisco Employee

hey abraham,

you can, but you probably don't want to. Let me explain:

in the XR sw account for drops differently then in IOS, so if you have a KPI that looks at ifdrops to determine an issue, XR will erroneously generate trouble; in XR we accumulate ANY drop under that SNMP counter (eg policer drop, acl drop etc).

Same as with cpu and memory, since XR manages mem same was as Linux or OSX, the free mem is not necessarily a point of concern, since some mem is marked as "ready for use", eventhough not marked free as such.

Managing cpu and mem for IOS to XR is not the same, and that is most important. Best practices? Hard to define, this is Linux based, so you need to "manage" that accordingly.



Rising star
Rising star

Hi Xander,

Thanks a lot for your answer. One final question based on your previous reponse. Does Monitoring Interfaces + Traffic also have the same "variation" for this platform in comparison with regular Cisco Routers?






Cisco Employee
Cisco Employee

It used to, but I want to say that in the recent codes such as 513 the implementation is rather robust. There is a delta between the interface CLI counters and the snmp counters, this simply because of the caching, the cli pulls it directly from the hardware, while snmp reads it out of the cache that gets periodically updated.



Benjamin Bartsch

Xander - great to see you at Cisco Live and I appreciate you taking the time to meet with us to discuss BNG.

Quick question for you on SNMPv2c on v5.1.3.  What is the command to show the 'hits' on the ACL?  I can't seem to find the ingress location to reference.  My customer's SNMP server is unable to poll the 9k, but he is receiving traps from the 9k.  I suspect there is a configuration issue on the SNMP server somewhere.  We can ping between loopback0 on the 9k and the A.B.C.D address on the server.  I'm not seeing any packets coming in to the 9k from the SNMP server.


Here is my config:


snmp-server host A.B.C.D traps version 2c [string]
snmp-server community [string] RO SNMP_ACL
snmp-server traps
snmp-server trap-source Loopback0


ipv4 access-list SNMP_ACL
 10 remark SNMP_ACL
 20 permit ipv4 host A.B.C.D any
 1000 remark ** DENY EVERYTHING ELSE **
 1010 deny ipv4 any any

RP/0/RSP0/CPU0:CORE-1#sh snmp
Wed Jun 17 15:21:27.144 CDT
0 SNMP packets input
    0 Bad SNMP version errors
    0 Unknown community name
    0 Illegal operation for community name supplied
    0 Encoding errors
    0 Number of requested variables
    0 Number of altered variables
    0 Get-request PDUs
    0 Get-next PDUs
    0 Set-request PDUs
1265 SNMP packets output
    0 Too big errors (Maximum packet size 1500)
    0 No such name errors
    0 Bad values errors
    0 General errors
    0 Response PDUs
    1265 Trap PDUs

SNMP logging: Enabled
    Logging to Notification host: A.B.C.D, udp-port: 162
    Trap Statistics
    Number of pkts in Trap Queue: 0
    Maximum length of Trap Queue: 100
             Number of pkts sent: 636
          Number of pkts dropped: 629

    Inform Statistics
       Number of Informs sent: 0
    Number of Informs retries: 0
    Number of Informs pending: 0
    Number of Informs dropped: 0 



Cisco Employee
Cisco Employee

hey Ben!! yeah that was really awesome!! enjoyed our bng talk very much also!

say for this issue, do you have MPP configured? (management plane protection).

if so, it may be necessary to enable the interface that receives the snmp request to have snmp allowed. (check the local packet transport services document for more detail or the cisco live 2014 sanfran id 2904 for more details on LPTS).

show access-list should report it, but it sounds like the requests are not even coming in!

if the acl is removed do oyu see the requests coming in? if still not it must be MPP related, so lets try to add the interface to the mpp section and enable that interace to allow inband snmp.



Benjamin Bartsch

You nailed it - this customer is doing in band management and I never opened up SNMP in MPP.  Once SNMP peer is added to the backbone interfaces in MPP we see ACL hits and SNMP working.  The security works too well on the 9k!

Thanks again, Xander.

Cisco Employee
Cisco Employee

super! great we found it!

ha yeah, that lpts works pretty well!



Scott Ulmen
Community Member

I am looking at the output from "show snmp mib statistics" and wonder about the "COUNT" column.  Does anyone know what timeframe this reflects?  i.e. Is this since reboot, last 15min, etc? 

My output gives me a couple OIDs in the that show an avg response time >100000ms, but only show a 1 for count.


Thanks in advance for the assist!

Cisco Employee
Cisco Employee

hi scott! its indicative of the number of queries it had received on that mibD:



RP/0/RSP0/CPU0:A9K-BNG#proc restart mibd_interface
Thu Sep 10 13:47:44.450 EDT
RP/0/RSP0/CPU0:Sep 10 13:47:44.479 : sysmgr_control[65900]: %OS-SYSMGR-4-PROC_RESTART_NAME : User root (con0_RSP0_CPU0) requested a restart of process mibd_interface at 0/RSP0/CPU0
RP/0/RSP0/CPU0:A9K-BNG#show snmp mib statistics   
Thu Sep 10 13:47:48.901 EDT
Object ID                               COUNT     AVG[ms]   MAX[ms]   MIN[ms]   MAX_TS         

Group:interface <<< no queries now!

running a walk:


20260: ifNumber.0 (INTEGER) 188
20261: ifNumber.0 (INTEGER) 188
20262: ifNumber.0 (INTEGER) 188
20263: ifNumber.0 (INTEGER) 188

Group:interface                         20264     <1        <1        <1        Sep 10 13:48:25.201

ok one off :) but good enough right :)


Scott Ulmen
Community Member

WOW - thanks for the quick response!

OK, so it looks like that increment then continues to count up since the process was last started.  That helps a lot.  Assuming that I have been running for some time, the following shouldn't be an issue?

****SNIP****            1         100006    100006    100006            1         100007    100007    100007            1         100007    100007    100007            1         38913     38913     38913 



Cisco Employee
Cisco Employee

10.106 is the pw mib.

this mib is known to have some performance issues and I think only recently we are adding it back into service for limited scale.

the query time for this one event that it got was 100secs that is too much of course, but depending on release you have you may see this mib not supported at all or some perf issues.


Scott Ulmen
Community Member

Good morning-


I'm looking for some advice/clarification on changes that I'm looking to make. Let me start with a little background. 


Our SNMP environment has multiple platforms (a mix of IOS and IOS XR systems) - unfortunately we have little access to in regards to the configuration of the various SNMP management systems polling the network. This is putting a strain on the IOS XR platforms such that much of the needed information is not getting out (due to time outs). We have pulled 'sh snmp mib statistics' and made a list of higher level OIDs that we would like to start with in an attempt reduce this strain (see attached). Our main priority (a must have) is the IF MIB (access to IF statistics) we need this to manage the network. Our study revealed 72 different MIB families based on grouping the polled OIDs by the first 5 or 6 descriptors. We find the requested information ranges from ATM to IPV4/6 to CFM... many of which are outside of our primary objective (Interface stats).


My questions are as follows:


* Are any of the OIDs that are on my "no" list likely to be polled internally by the system? i.e. Is there a chance / risk that I may break a service on the 9k by excluding any of the OIDs in question?

* Is there a way that we can quickly determine if any of the OIDs are NOT supported in the IOS-XR Mib set?


As always, thanks in advance for any replies!

Cisco Employee
Cisco Employee

hi scott: the system itself wont poll info, only an "external" snmp get will induce access to the mib (dll's) inside.

as for the oid support, the mib list shows which mibs we are specifically testing against per release:

if a mib is not supported it wont return a value.

you can also use the mib"views" to restrict access to certain mibs if you like with the snmp-view commands.



Scott Ulmen
Community Member



I want to thank you again for your prompt responses!  That was just the type of response I was looking for.  Have a great weekend.

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