Within Cisco IOS XR there are servers who provide the services and clients who use the services. A particular process can have a number of threads who provide the same service. Another process can have a number of clients that might require a particular service at any point in time. Access to the servers is not always available, and if a client request access to a service it sits there and waits for the server to be free. In this case the client is said to be blocked. This is called a blocking client server model. The client might be blocked because it waits for a resource such as a MUTEX, or due to the fact that the server has not yet replied.

Issue a show process ospf command in order to check the status of the threads in the ospf process:

RP/0/RP1/CPU0:CWDCRS#show process ospf
                  Job Id: 250
                     PID: 110795
         Executable path: /disk0/hfr-rout-3.2.3/bin/ospf
              Instance #: 1
              Version ID: 00.00.0000
                 Respawn: ON
           Respawn count: 1
  Max. spawns per minute: 12
            Last started: Tue Jul 18 13:10:06 2006
           Process state: Run
           Package state: Normal
       Started on config: cfg/gl/ipv4-ospf/proc/101/ord_a/routerid
                    core: TEXT SHAREDMEM MAINMEM
               Max. core: 0
               Placement: ON
            startup_path: /pkg/startup/ospf.startup
                   Ready: 1.591s
               Available: 5.595s
        Process cpu time: 89.051 user, 0.254 kernel, 89.305 total
JID    TID  Stack pri state        HR:MM:SS:MSEC NAME
250    1      40K  10 Receive       0:00:11:0509 ospf
250    2      40K  10 Receive       0:01:08:0937 ospf
250    3      40K  10 Receive       0:00:03:0380 ospf
250    4      40K  10 Condvar       0:00:00:0003 ospf
250    5      40K  10 Receive       0:00:05:0222 ospf

Note that ospf process is given a Job ID (JID), which is 250. This never changes on a running router and generally on a particular version of Cisco IOS XR. Within the ospf process there are five threads each with their own Thread ID (TID). Listed is the stack space for each thread, the priority of each thread and its state.