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v5 Written: IOS XE Notes

v5 Written: 1.1.a Describe the basic software differences between IOS and IOS XE

* Runs an instance of IOS 15 (IOSd) over a Linux kernel

* Differences from IOS
– system boot
– internal architecture
– “certain commands” (there are several references to commands being different, but no definitive list of what these commands are)
– ISSU (In-Service Software Upgrade)

* Separation of management functions of Cisco IOS (control plane) from forwarding of packets (data plane); improves performance and reliability
because of isolation

* Allows use of multicore CPUs

* Platform abstraction

* Linux architecture provides for improved service (application) integration
– Common Management Enabling Technology (COMET)

* Forwarding and Feature Manager (FFM) – Control plane

* Forwarding Engine Driver (FED) – Data plane


* Commands that are different:
show version
show process cpu
show process memory
show process cpu detailed
show process cpu detailed process iosd
show version running (shows the IOS release 15 image, same thing as image name)


* ASR1000 specific commands (should not be on the test):
show version (to get total memory installed)
show processes memory (doc used “processes” instead of “process”; to check memory usage of IOSd)
show platform software status control-processor brief (to check memory usage on IOS XE)
monitor platform software process {fp|rp} {active|standby}
– then hit Shift+M
show platform hardware qfp active infrastructure exmem statistics (to check memory usage of the QuantumFlow Processor (QFP))


* I saw one reference of wireshark being able to use one CPU core when used, but couldn’t find anything else mention this.

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