One of the tools at your disposal during the JNCIE-SP exam is the JUNOS CLI itself and there is an awful lot of documentation stored in it.
The first tool you will need to learn how to use to take advantage of this is “help apropos XXX”.
Here are a couple of example outputs:
lab@R1> help apropos anycast help topic pim examples anycast Overview of anycast RP example help reference pim local-address Local address for anycast rendezvous point help reference pim address-anycast Anycast rendezvous point addresses in RP set help reference pim anycast-pim Anycast rendezvous point using PIM help reference pim rp-set Set of up to 15 rendezvous point addresses for anycast RP lab@R1> help apropos interpro help topic layer3-vpns examples-cofc Sample interprovider and carrier-of-carriers VPNs help topic layer3-vpns examples-cofc interprovider-ebgp Overview of interprovider with multihop MP-EBGP help topic layer3-vpns examples-cofc interprovider-isp Overview of interprovider with MP-EBGP between ISP peers help topic layer3-vpns examples-cofc terms Terms in carrier-of-carriers and interprovider examples help topic layer3-vpns interprovider Overview of interprovider VPNs
As you can see above, “help apropos…” acts as a sort of keyword search for the help system.
Beyond that, “help apropos…” can provide a context-sensitive search CLI commands.
lab@R1> help apropos pfe clear pfe Clear Packet Forwarding Engine information show pfe Show Packet Forwarding Engine information show pfe version Show pfe version ... lab@R1> help apropos uptime show system uptime Show time since system and processes started show chassis pic Show Physical Interface Card state, type, and uptime
[edit protocols bgp] lab@R1# help apropos override set group as-override Replace neighbor AS number with our AS number set group neighbor <address> as-override Replace neighbor AS number with our AS number [edit policy-options] lab@R1# help apropos route-type set policy-statement term from route-type Route type set policy-statement from route-type Route type
Help Reference and Help Topic
Your mileage will vary with these help outputs. The output seems to be nearly verbatim copy from the JUNOS documentation. Where you would normally have images, you instead find a URL for a GIF. That may not turn out to be too helpful for someone who is completely blanking on how to configure something but if you forget a detail or two, it can probably save you a lot of time.
For instance, I forgot about which MPLS TTL mechanism supported LDP. So I ran a search and pulled up the reference for no-propagate-ttl
lab@R1> help apropos no-prop help topic mpls no-propagate-ttl TTL value is decremented by 1 only help reference mpls no-propagate-ttl TTL value is set to 255 lab@R1> help reference mpls no-propagate-ttl ... Description Disable normal TTL decrementing. You configure this statement once per router, and it affects all RSVP-signaled or LDP-signaled LSPs. When this router acts as an ingress router for an LSP, it pushes an MPLS header with a TTL value of 255, regardless of the IP packet TTL. When the router acts as the penultimate router, it pops the MPLS header without writing the MPLS TTL into the IP packet.
By chance, this happened to be the correct one to configure to support LDP.
There is some seriously detail information available if you need it. For an example, see “help topic pim auto-rp”. It tells you just about every step you need to configure.