Cisco Tips & Tricks

October 24, 2008

Day 3, 4 and 5 of Narbik’s Bootcamp

Filed under: bgp, ccie, IP Routing, QOS, Technology and Software — ciscotips @ 6:22 pm

Sorry for posting late, Narbiks bootcamp was fun. Its worth attending his bootcamp if you are somewhere in the mid-tier of your CCIE preparation. Narbik recommends to cover Soups-to-nuts before you attend his bootcamp and he is right., otherwise it can be too much of information for you in 5 Days. Here is what he covered in last three days.

Day 3:- BGP

It was a big day for me. Day 3 is a BGP day, youy have  almost 200 pages worth of BGP labs. Narbik’s BGP  lecture style is totally different then the conventional CCIE Instructors. He doesn’t start BGP with Attributes or BGP states. He attacks on BGP optimization and then buiold you towards attributes and other advance topics. Simply awesome. He will start with MSS ( Maximum segment size) , Scan time, Advertising Interval and then take you to Memory pools, templates and Peer-groups. At last he will talk about BGP states, Aggregation, Attributes and some awesome route-filtering techniques. I will say that was my best BGP class.

Day 4:- RIPv2 and QoS

Another big day which was dedicated to Qos and 2 hours worth of lecture for RIP v2.  He showed what RIPv2 is worth of. People normally ignore RIP but if you know what all you can do with RIP. You will never be disappointed to use it for your small size network. He covered optimization, RIP updates,Filtering,redistribution,authentication  building it on some advanced scenarios.

Qos:- Qos

Qos was never my strong topic, although I am using it regularly in my job but I always struggled on few advanced topics. I should not have a problem in Qos after attending Narbik’s lecture.  Narbik started Qos with Queuing. He covered, CBWFQ, LLQ, filtering,CBWRED,Shaping, CAR,policing and SRR. Pretty good lecture indeed!

FInal Day ( Day 5 Multicast and CCIE lab tips).

Narbik covered multicast Addressing, Delievery Methods, Manipulating MCast Traffic, Dense,sparse modes, MSDP,ANycast and udp helper. I still have to work on Multicast labs but I am sure  I can practice on it  and grasp what I need most for my Lab.

As I am going through Narbik’s Advance 6 volume CCIE workbooks, I will try to post tips and tricks on various technologies going forward.

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October 10, 2006

Cisco Simulator for CCIE’s

Filed under: bgp, cisco, IP Routing, ospf, QOS — ciscotips @ 8:17 pm

what cisco simulator !!! Are you crazy… No I am not!

My frenz never believed me that I am using a cisco simulator for my CCIE lab practice. My simulator can support direct images of 7200 and now 3600 series. Hard to believe!

check this out

http://www.ipflow.utc.fr/blog/

June 7, 2006

How to block skype

Filed under: Access-lists, QOS, Router, security — ciscotips @ 4:36 am

On April 4th 2006, Cisco released IOS version 12.4 (4) T. Cisco introduced much awaited Skype classification in NBAR . So now with simple policy you can block skype. Skype can be blocked in a similar way as we use to block kazza,limewire and other p2p applications.

Example:-

NBAR configuration to drop Skype packets

class−map match−any p2p
match protocol skype

policy−map block−p2p
class p2p
drop

int FastEthernet0
description PIX−facing interface
service−policy input block−p2p

If you are unsure about the bandwidth eating applications being used in your organisation. you can access the interface connected to the Internet and configure following command

ip nbar protocol-discovery.

This will enable nbar discovery on your router.

Use following command:-

show ip nbar protocol-discovery stats bit-rate top-n 10

it will show you top 10 bandwidth eating applications being used by the users. Now you will be able to block/restrict traffic with appropriate QoS policy.

we can also use ip nbar port-map command to look for the protocol or protocol name, using a port number or numbers other than the well-known Internet Assigned Numbers Authority (IANA)-assigned) port numbers.

Usage as per cisco:-
ip nbar port-map protocol-name [tcp | udp] port-number

Up to 16 ports can be specified with this command. Port number values can range from 0 to 65535

May 20, 2006

QoS-Rate-Limiting Tip

Filed under: Access-lists, QOS, Router, Switching, Technology and Software — ciscotips @ 7:17 am

QOS feature that performs rate-limiting and packet classification is called CAR-Committed Access Rate.

Here is a quick tip that limits an Internet based traffic
(primarily http and FTP) to 512K, with a nice, fat burst.

First create the access lists.

access-list 100 permit tcp any any eq www
access-list 100 permit tcp any any eq ftp

Then apply rate limiting rules to the appropriate interface:

interface Serial1/0
bandwidth 2048
ip address 172.16.100.2 255.255.255.252
rate-limit input access-group 100 512000 1024000 2048000 conform-action transmit exceed-action drop
rate-limit output access-group 100 512000 1024000 2048000 conform-action transmit exceed-action drop

It will limit only http and ftp trafic, for other corporate web applications running on different ports, it will still get full E1 bandwidth.

Warning:-If, in a rate-limit rule, you reference an access list that does not exist, the rule will match all traffic. Usually not good.

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