Archive for the 'Cisco' Category

Interface Hardware Queuing (tx_limited).

Monday, June 23rd, 2008

There are two major queuing lines available. The one that we’ve been playing with is only software based. From this software queuing we implement CB-WFQ, PQ, LLQ and other queuing methods. Whatever done from this software queuing packets then passed to hardware queuing that is more strict and using only FIFO as queuing method.
Imagine you [...]

Congratulations Brian Dennis - 5 Times CCIE!

Saturday, June 7th, 2008

Cisco Design Best Practices for Data Center

Friday, May 30th, 2008

This tool is provided to help users gain access to design and test informatio in and intuitive, interactive way.
To find the network design guidance you need for a specific data center project, go to the CVD-I tab and navigate the topology.
To access the test descriptions, results, and device configuration of the latest fully [...]

Ipv6 Overlapping Errors?

Friday, May 9th, 2008

R2(config)#int lo0
R2(config-if)#ipv addr fec0::2:1/112
% FEC0::2:1/112 can not be configured on Loopback0, overlapping
R2(config-if)# ipv addr FEC0::12:3/112
% FEC0::12:3/112 can not be configured on Loopback0, overlapping
R2(config-if)# ipv addr FEC0::222:1/112
R2(config-if)# ipv addr FEC0::2:1/112

R2(config-if)#do sh ver | i IOS
Cisco IOS Software, 3600 Software (C3640-JS-M), Version 12.4(18), RELEASE SOFTWARE (fc1)

Why am I getting these overlapping errors?

Congratulations to CCIE fellows!

Thursday, May 8th, 2008

Arden Packeer. CCIE #20716
http://ardenpackeer.com/blog/ccie-20716/
Victor Cappuccio. CCIE Number: 20657
http://vcappuccio.wordpress.com/2008/04/30/ccie-number-20657/
Ethan Banks. CCIE #20655
http://www.cciecandidate.com/?p=412
and
Triple CCIE
Joe Harris. CCIE # 6200 (R&S, Security & SP)
http://6200networks.com/2008/04/27/i-passed/

OSPF Network Types: Point-to-Point - Cisco Standard

Friday, April 25th, 2008

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 [...]

OSPF Network Type: Point-to-Multipoint, Non-Broadcast, Cisco Proprietary

Thursday, April 24th, 2008

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

Wednesday, April 23rd, 2008

Partial-mesh or star network topology.
One IP Subnet.
Hello Timer 30 seconds.
Automatic adjacency, no DR/BDR elected.

OSPF Network Types: Non-Broadcast

Tuesday, April 22nd, 2008

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?

OSPF network types: Broadcast

Monday, April 21st, 2008

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 [...]