BSCI Exam - Passed!

Well, I've just got back from the test centre and I'm pleased to say that I passed!!

It was a bit touch and go though as I think there was about 1 minute 30 seconds left on the clock.

No rest though as I've already started CCNP SWITCH at my local Cisco Networking Academy.

As you'll guess, most posts from now on will be SWITCH related.

Thanks
Jonathan

BSCI - ISIS - Adjacency requirements

For an ISIS adjacency to come up the following criteria must match:
i) MTU  - default is 1497
ii) Router Levels - L1, L1/L2, L2 only
iii) If L1 router, the IS must be in the same area
iv) System ID's must be unique
v) Authentication (if used)

Adjacency is formed after a 3-way handshake. The stages are DOWN - INIT- UP

The adjacency is up if the neighbor has put you identity in their hello packet.

BSCI - ISIS - Show commands

The following show commands can be used for ISIS:

#sh ip protocols
-Displays: active interfaces, routing information sources (neighbors), whether summarisation is in effect, last update

#sh clns protocols
-Displays: System ID, ISIS router type (L1| L1/L2| L2), Area IS, active interfaces

#sh clns neighbor
-Displays:  Single Line summary of neighbors, system id NAMES, SNPA, State (Up or Down), hold time, router type, protocol

#sh clns neighbor detail
- Displays: multi-line details of neighbors, neighbor info, Area ID, up time, ip of neighbor

#sh isis database
-Displays:  L1/L2 routers you see 2 Db's, * indicates the DIS (which is elected either via the interface cmd #isis priority [number] or is a priority is not set the DIS is the device with the highest SNPA which in this case it the Ethernet MAC address on the router)

#sh isis topology
- Displays: system, metric, next-hop, egress interface to get to next-hop, SNPA of next-hop router

BSCI - Manipulating Routing Updates - Private IP address scopes

RC 1918 states that IANA has assigned the following ranges to be 'Private'

10.0.0.0        -   10.255.255.255  (10/8 prefix)

172.16.0.0      -   172.31.255.255  (172.16/12 prefix)

192.168.0.0     -   192.168.255.255 (192.168/16 prefix)

BSCI - OSPF - Area types and LSA's

Note to self:

Routers in a stub area will have a default route to use to reach external destinations; routers in total stub areas will have a default route to use in order to reach both external and inter-area networks.

BSCI - Study Pointers - IS-IS

IS-IS:

• Level 3 routing - routing between separate routing domains
• All ES's and Level1 IS's must have a unique system ID area wide
• IS-IS is able to have more routers in an area compared to OSPF and fewer Link-State PDU's are used.
• In Frame-Relay, the highest local DLCI is used to elect a designated IS (if all priorities are the same)
• the cmd R1(config-if)#isis password [password] [level] -sets authentication for a specific link, when level is not specified the default is level 1
• an INIT state can exist is there is a mis-matched authentication config or mis-matched MTU.

Review Documents

It's been a while since I last posted. Mainly due to personal commitments at home and work but also through a lack of inspiration.

Out of the blue I had a message for an old colleague at the weekend to say that one of my posts got him out of a fix in his new role and that made me think again.

Since my last post I've been covering Redistribution, Distribution Lists, and Route Maps. I'm also about half way through my BGP studies which on the face of it seem fine. That said I haven't got in to the fine tuning of the protocol  yet and that doesn't look pretty.

I'm intending on covering of the main configuration and verification commands of the previous topics mainly to keep them fresh in my mind as I look forward to Multicasting, IPv6 and the case studies on my BSCI Networking Academy course.

BSCI - IS-IS - Differences between IS-IS and OSPF

• OSPF supports 50 routers per area
• IS-IS can support up to 1000 routers per area
• OSPF includes more features, including route tags, stub/nssa configuration, on demand circuits
• OSPF requires many LSA's to advertise and withdraw routes.
• IS-IS only requires one LSP per IS-IS router in a given area.
• IS-IS doesn't support a Backup designated router (BDR).i.e. you only have the primary Designated Intermediate System (DIS).
• IS-IS repeats the DIS election process every time a new router is added to an area.
• If the new router has the same of higher priority it will become the new DIS.
• IS-IS is designed to be deterministic so that the same set of IS-IS routers always produce the same DIS.
• Every time a DIS changes a new set of LSP's are flooded to the neighbours.
• IS-IS form adjacencies with all routers in the area not just the DIS.
• OSPF uses a scaled metric by default where as IS-IS uses a default metric of 10 for all links.

BSCI - IS-IS - High level operations

Routers using IS-IS issue Hello packets out of all interfaces enabled for IS-IS to discover neighbours and establish adjacencies.

Routers will become IS-IS neighbours  if their Hello packets contain certin information for the creation of an adjacency.

Routers then build Link-State Packets (LSP's) based on the adjacencies present and then flodd the LSP's to their neighbours.

All routers then build a Link-State Database (LSDB) using the information in the received LSP.

The router then runs the SPF algorithm, the shortest path to each dsestination is then calcultated and added to the Routing Information Base (RIB or OSI routing table).

Next, the Partial Route Calcultion is performed using the IP information contained within one of the Time, Length, Value (TLV) fields in the LSP. This generates shortest paths for IP traffic and in turn is entered in to the IP routing table.

CCNP ROUTE Cert Kit Giveaway

Rofi Neron over at ITDualism.wordpress.com has a Cisco CCNP Route Cert Kit to giveaway.

To enter check out his competition here: http://itdualism.wordpress.com/2010/03/03/giveaway-route-cert-kit/

Well worth the time and an excellent opportunity to bag some Cisco Press material.

Good Luck!!