If you think Apple Mac keyboard was cool, think again.
Best Keyboard Design by Maximus.
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Monthly Archives: April 2008
Running the Numbers by Chris Jordan
Depicts one million plastic cups, the number used on airline flights in the US every six hours.
For complete art appreciation, visit http://www.chrisjordan.com/current_set2.php?id=7
OSPF Network Types: Point-to-Point – Cisco Standard
This is the simplest network type for OSPF. Two routers connected via point-to-point link. For this particular network, there is no need to have DR and BDR. Why, because each router will sending updates to each other and having DR and BDR will not change the situation. Each router will send multicast hello packets using address 224.0.0.5.
Default OSPF hello and dead intervals is 10 seconds and 40 seconds, respectively.
- Partial-mesh or star network topology, using subinterface.
- Different subnet for each subinterface.
- Hello Timer 10 seconds.
- Automatic adjacency, no DR/BDR elected.
OSPF Network Type: Point-to-Multipoint, Non-Broadcast, Cisco Proprietary
- Partial-mesh or star network topology.
- One IP Subnet.
- Hello Timer 30 seconds.
- Manual adjacency, no DR/BDR elected.
OSPF Network Types: Point-to-Multipoint – RFC Standard
- Partial-mesh or star network topology.
- One IP Subnet.
- Hello Timer 30 seconds.
- Automatic adjacency, no DR/BDR elected.
OSPF Network Types: Non-Broadcast
Non Broadcast Multi Access (NBMA) – RFC 2328 Standard
- Full or partial-mesh network topology.
- One IP Subnet.
- Hello Timer 30 seconds.
- Manual adjacency, DR/BDR elected.
From the previous example, we see that we’re using broadcast mode on NBMA network. What if we don’t want to use broadcast mode since it’s a non-broadcast network, anyway?
Work through conflicting pressures?
Wandering around looking the job market and found this.
Demonstrated enthusiasm and drive with the ability to work through conflicting pressures and priorities.
Why would a person want to work in this type of job? Pressures are always there. But conflicting pressures? This company must have a really big problem since the word conflicting and pressures should not be set together.
OSPF network types: Broadcast
Configuring OSPF network can be cumbersome considering the requirement for each router to send update to other routers to create the same topology table. Obviously, in the big network with more routers, there will be more multicast updates to any routers which mean more traffic. This is where OSPF area comes into play. Rather than creating a one large network, OSPF can make smaller network partitions which connect to backbone network called Area 0. Having this smaller network partitions connect to Backbone network will create hierarchical network topology.
Still, inside an OSPF area, there are significant multicast packets sent to routers. Therefore OSPF has DR and BDR to reduce the multicast packets. Rather than sending those packets to all routers within the area, routers just need to send update to DR and BDR, then these two routers will multicast the packets to the rest of the network. Happened to remember about Route Reflector on BGP. It’s quite similar concepts.
Having those two requirements, some tweakings need to be made in order to make OSPF works. There are 3 Cisco proprietaries and 2 RFC standards known to configure OSPF network.
- Non Broadcast Multi Access (NBMA) – RFC 2328 Standard
- Broadcast – Cisco Proprietary
- Point-to-Multipoint – RFC Standard
- Point-to-Multipoint, Non-Broadcast – Cisco Proprietary
- Point-to-Point – Cisco Standard
This is part 1 the next 5 parts writing.
nslookup 69.69.69.69
Not the right theme, apparently.
I’ve been looking for the right theme for this site but none really can fit the criteria I need. This theme I’m currently using is not working quite well as I expected.
I’m not aiming for sophisticated design. Just a simple design with long content viewing and support right and left embedded image.
Duh, been searching for a while but none I could find.
For the mean time, stay tune (and put up) with this theme as I’m planning to change it, again.