Arnaud Fenioux 's Personal Home Page


The opinions expressed here are my personal opinions. My current or past employers are not responsible for what I write here or the comments left by site visitors.

Switch CAM, TCAM and SDM

August 20, 2014 - Arnaud
Categorie: Technical
Tags: cisco

Cisco Catalyst switches use CAM and TCAM to store MAC addresses, ACL, QoS tables in order to have wire-speed switching : they are ASICs and search the entire memory in one operation.
The CAM (Content Addressable Memory) stores MAC addresses, VLAN and ports assignments. During a lookup, the CAM returns the address where the data is stored (the inverse of regular RAM). It is used on L2 swich.

dBm / mW and DWDM

August 7, 2014 - Arnaud
Categorie: Technical
You will learn in this ticket : dBm/mW equivalence, Appx Attenuation/range (km), DWDM Channels length and Freq:
20dBm = 100mW
10dBm = 10mW
  3dBm = 2mW
  0dBm = 1mW
-3dBm = 0,5mW
-10dBm = 0,1mW
-20dBm = 0,01mW
more below:

Juniper basics

August 7, 2014 - Arnaud
Categorie: Technical
Tags: Juniper
First step is to read these "day one" free books :
I choosed Configuring Junos Basics, and Junos for IOS Engineers.

RIPE database documentation

July 29, 2014 - Arnaud
Categorie: Technical
Tags: Web

get help to query RIPE Database :

telnet 43

Documentation page :

Query flags cheatsheet :

two alias I use in my bashrc :


July 14, 2014 - Arnaud
Categorie: Technical
Tags: cisco

I've not yet deployed such techno, but I found some great presentations to better understand theses concepts & configuration :



Nice Graphs : Visio or Dia?

June 12, 2014 - Arnaud
Categorie: Divers

Actually, I've choosed yEd : It's free (but sadly not open-source), availiable on many OS, and almost as good as omnigraffle

You will find below my "palette" with a nice set of network icons, simply do :
Edit -> Palette Manager -> Import Section...

File Upload: 

L2 ACL / MAC ACL vs Port Security

May 19, 2014 - Arnaud
Categorie: Technical
Tags: cisco

Cisco devices can filter mac addesses inbund with port-security or ACL, but remember ACL are checked on hardware with ASICS on the ports, and Port Security is checked in soft (and can cause big trubble when used in restrict/protect mode when many violations occur):

---Port-security on cat 6500---

in the example we allow 100 mac addresses on this trunk port, but only 2 specific mac on the vlan 4 (interface conf mode): 

Enable SSH && disable telnet

April 30, 2014 - Arnaud
Categorie: Technical
Tags: cisco

Telnet is "bad", this is how to enable ssh and disable telnet login, and BTW we only want ssh v2 as v1 is vulnerable to several attacks:
When asked choose a least 1024bits for the key

hostname switch
ip domain-name mydomain.tld
aaa new-model
crypto key generate rsa
ip ssh version 2
line vty 0 15
 transport input ssh

Remember to add ACL, this is always a good thing

BGP references

March 23, 2014 - Arnaud
Categorie: Technical
Tags: cisco
I have put here lots of links I use for my presentations, and that could be interresting for anyone :
PDF Slides of my BGP workshops (in French)
What is Peering?

Vlan Shaping

March 11, 2014 - Arnaud
Categorie: Technical
Tags: cisco
conf t
  mls qos

  class-map match-any vlan123
   match vlan 123

  policy-map ratelimit
   class vlan123
   police cir 1000000000
   confirm-action transmit
   exceed-action drop

  int gi0/1
    service-policy input ratelimit


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