Monitoring Cisco 2600, 2800 Series


Device Type Object Identifier Mibs
Cisco 2600 Series
  • . (cisco2610)
  • . (cisco2611)
  • . (cisco2612)
Cisco Products Mib
Cisco 2800 Series
  • . (cisco2851)
  • . (cisco2801)
  • . (cisco2821)
  • . (cisco2811)
What to Monitor
When monitoring the routers for performance, its hard to pin down any one resource that could lead to performance degradation. It could be any or a combination of the following reasons that lead to poor performance:
Performance of the CPU:Core router functions like, routing protocol processing, process packet switching etc, are handled in memory and share the CPU. Thus, if CPU utilization is very high, it is possible that a routing update is not handled or a process-switching packet is dropped. The CPU performance degrading on routers is a frequent issue caused due to interrupts or slow processes on the router. The router stops sending routing updates to other routers, the performance is slow and the services on the router fail to respond, impacting the business. Proactively watching the CPU health is a must. Read more on troubleshooting high cpu utilization issues.
Performance of RAM: Memory leaks or fragmentation are common causes leading to poor memory performance. Identifying memory allocation failures or leaks early on helps in optimzing the memory performance. Monitoring basic memory metrics like memory utilization, free memory, used memory etc will serve as a good indicator of the RAM health.Click here to read further on troubleshooting memory problems on Cisco routers

Buffer Monitoring: The Route Processor divides its processor memory into 6 pools with each pool comprising of many memory blocks of equal size. These memory blocks are called buffers. The buffers are used for handling traffic landing on the router or when packets are being switched. When a requested buffer is not available, a 'buffer failure' is detected and the buffer pool manager process tries creating new buffer to avert further failures. Insufficient memory limits creating of new buffers. So buffers are crucial resources to be monitored on a router, especially the number of failures and buffer-create failures due ti inadequate memory. A consistent failure of buffers requires tuning.
Bandwidth Monitoring: The percentage of network bandwidth used by the traffic coming into and going out of the network needs monitoring. If there is a consistent increase in the bandwidth utilized by the Rx Traffic (incoming) or the Tx Traffic(out-going), errors and discards occur leading to data loss. The network bottlenecks can be eliminated by analyzing the traffic indepth using Netflow.
Monitor SNMP OID Details Additional Resources
CPU Monitors TOP ^
CPU Usage (5 mins average) . This variable returns the 5 minute 'exponentially-decayed moving average' of the CPU busy percentage. Which means that it is an averaging model that gives higest weight to the latest data points and also eliminates the transcient wild spikes in the last 5 minute Collecting CPU Utilization data
CPU Usage (1 min average) . This variable returns the1 minute 'exponentially-decayed moving average' of the CPU busy percentage. Which means that it is an averaging model that gives higest weight to the latest data points and also eliminates the transcient wild spikes in the last minute.
CPU Usage (1 sec) . It is the CPU busy percentage in the last 5 second period. Not the last 5 realtime seconds but the last 5 second period in the scheduler. Note that the utilization bits 99 % when continuously polled at one-second intervals, an overkill.
Memory Monitors
Memory Utilization .*100)/
(. (.
It is the percentage of memory used from the total memory available on the router. The expression used here is : (Memory used X 100)/(Memory used + Free Memory).  
Buffer Monitors TOP ^
Buffer Failures .
A processor asks for a buffer of specific size and is granted if available in the existing pool and generates a 'miss' if not available, resulting in a buffer failure. When a buffer-create fails, it leads to packet drops, which means loss of data. Buffer failures are one of the most common reasons for packet drops. This is a parameter to be watched on the routers for performance. More on buffer pools
Total Huge Buffer Misses .
The buffer pools (memory blocks) are grouped as Small, Medium, Big, VeryBig, Large, and Huge. Depending on the size of the packet to be passed, a request is made to one of these buffers. A corresponding 'buffer miss' is triggered when there is not enough memory available in that pool. 'Total' misses are triggered when a miss is generated due to insufficient resource across all the pools.

Total Large Buffer Misses


Big Buffer Misses


Medium Buffer Misses


Small Buffer Misses


Total Huge Buffer Hits

Buffer 'hits' is the number of buffers that have been requested from the pool. The hits counter helps determine the pool that meet the highest demand for buffers.
Total Large Buffer Hits .

Big Buffer Hits


Medium Buffer Hits

Small Buffer Hits .
Traffic Monitors TOP ^
Rx Traffic . Rx Utilization is the percentage of the network bandwidth currently used by the received traffic on the network. A consistent high utilization indicates bottlenecks in the network and needs further troubleshooting.
Tx Traffic . Tx utilization is the percentage of the network bandwidth used up by the transmitted traffic. Again, a high utilization indicates network performance bottlenecks. Indepth traffic analysis using the Netflow module helps identify and free-up the bandwidth quickly.  
Rx/Tx Errors

Rx- .
Tx - .

The number of inbound packets (Rx) or out-bound packets (Tx) containing errors, preventing them from being delivered to the next layer protocol.  
Related Topics TOP ^

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