Back on studies

I have been away for some days, 2 weeks now I could not study 😦 . I was preparing Ericsson IP Networking Certifications, that I passed the associate (EC-201) and the professional (EC-301) level. It was not tough but kind of tricky and my experience on the products and Cisco helped me a lot. Find topics attached.

Now back to studies, real ones, I know you guessed right: CCIE R&S Lab preparation.
Tomorrow, next lab to work on is INE wk2 lab 6.

Nice moments and fun waiting for me. Hey do not think of clubbing, I meant labbing 🙂

D – 5 months

5 months to the lab, still many topics to master, many labs to do. QoS and IP Services and mutual redistribution still my enemies. Lot of work, short period between assignments. Other internal certifications to prepare by the end of this month.
It’s the combination of all this making CCIE lab preparation tough, very tough indeed. And that’s unique.
So let’s feel the moment and keep it up studying hard, even if sometimes I feel like screaming, oups! I said it 🙂

My OSPF Notes

This is my OSPF notes I took when I was working on OSPF technology specific labs.

### Avoid secondary IP advertisement ###
interface <type> <mod>/<num>
 ip ospf <pid> area <#> secondaries none### Disable Syslog logging for type 6 LSAs (MOSPF – not supported on Cisco) ###router ospf <pid>
 ignore lsa mospf

### OSPF Fast Hello Packets – Min dead-interval (1 sec) with hello-multiplier ###
interface <type> <mod>/<num>
 ip ospf dead-interval minimal hello-multiplier <3-20>

### OSPF name lookup — Display OSPF Router-id as router name ####
ip ospf name-lookup
ip host <name> <ip>

### OSPF network type LOOPBACK
Loopback and looped back interfaces use by default LOOPBACK network type, a host route (/32) is advertised for that interface instead of the real mask.

To advertise the loopback ip with real mask, use network type POINT-TO-POINT.
* ip ospf network point-to-point

### OSPF Authentication
-> Plain-text password
can be activated under router: * area <id> authentication
or under interface:            * ip ospf authentication
Authentication key is configured under interface:
* ip ospf authentication-key <string>

-> MD5 auth
can be activated under router: * area <id> authentication message-digest
or under interface:            * ip ospf authentication message-digest
Authentication key is configured under interface:
* ip ospf message-digest-key <key> md5 <string>

### VIRTUAL LINKS
Created between 2 ABRs, one of them should be connected to area 0.
Example: |R1|—-area0—-|R2|—-area1—–|R3|—-area2—-|R4| we should connect area 2 to area 0:
– on R2: * area 1 virtual-link <R3 RID>
– on R3: * area 1 virtual-link <R2 RID>

*** Virtual-links can’t be configured on a stub area, to fix the broken OSFP network we use GRE tunnels.
Create GRE tunnels on the ABRs (one connected to are 0) and advertise them in area 0.
* interface tunnel<#>
*  ip add <ip@> <mask>
*  tun so <ip@>
*  tun de <ip@>
*  ip ospf <pid> a 0

– Virtual-links Authentication
Simple password:

  * area <id> virtual-link <RID> authentication

  * area <id> virtual-link <RID> authentication-key <string>

MD5 Authentication:

  * area <id> virtual-link <RID> authentication message-digest

  * area <id> virtual-link <RID> message-digest-key 1 md5 <string>

*** When authentication is enabled on area 0 in a network using virtual-links,
this authentication should be enable on other ABRs where virtual-links are created ‘coz

those routers are part of area 0 too.

#############################################################################################

### OSPF COST
under interface configuration:
* ip ospf cost <1-65535>

### OSPF REFERENCE COST —— REF BW / BW = COST
By default OSPF cost is calculated based by default on fastethernet interface BW.
To change the refrence bandwidth use under ospf config mode:

* auto-cost reference-bandwidth <bw in Mbits>

This command should be used on every router in the OSPF domain. REF / BW = COST

#############################################################################################

### SUMMARIZATION
The Internal routes can only be summarized on ABRs, whereas the External (redistributed) routes can only be summarized on ASBRs.
– Internal summarization
* area <id> range <summary> <mask> …
!– where area id is the area to which the summary belongs, summarizes type 3 LSAs

– External summarization
* summary-address <summary> <mask> !– summarizes type 5 and 7 LSAs

– Disable creation of NULL0 route when using area range or summary-address command respectively
* no discard-route internal
* no discard-route external

#############################################################################################

### STUB AREAs
– Stub area can’t be used as transit area for virtual but GRE tunnel can be used instead
– A Stub area can not have an ASBR
– Every router and the ABR of that area should have “area <id> stub” command
– For totally stubby area (no type 3, 4 and 5 LSAs) the ABR should have “area <id> stub no-summary command.
– NSSA only receives or propagate LSA types 1, 2, 3 or 7.
area <id> nssa [default-information-originate] [no-summary]
* [default-information-originate] Originate Type 7 default (O*N2) into NSSA area.
* [no-summary] Originate Type 3 default (O*IA) into NSSA area. Do not send summary LSA into NSSA.

– By default the cost of default route injected into a given area is 1, this can be changed using: * area <id> default-cost <0-16777215>
#############################################################################################

### OSPF FILTERING
– To filter a given prefix from the routing table, use:
# distribute-list {acl#|acl_name|prefix|route-map} in [interface]
This has effect only on the router where it is configured, except if the prefix that is being filtered is coming from area 0,
in which case the prefix will be filtered from the database.

– Inter-area filtering: area <id> filter-list prefix <prefix_name> {in|out}. This ONLY works for LSA type 3.

– Filter LSA type 1 (and only type 1) from being injected into a given area:

* area <id> range <summary> <mask> not-advertise

– * distribute-list <acl#> out : only used on ASBR (else it will not have any effect whatsoever) to filter LSA type 5s or 7s from the OSPF database.
We can also use on the ASBR, * summary-address <summary> <mask> not-advertise.

– Prevent flooding of ALL OSPF LSAs out of a given interface:
  interface <type> <num>
   ip ospf database-filter all out

– Prevent flooding of ALL OSPF LSAs to a given neighbor that is reachable through   an interface that has a point-to-multipoint network type at a given ip @.

* neighbor <id> database-filter all out

### TRAFFIC REDIRECTION
– To set a maximum metric for self-originated router-LSAs:

  max-metric router-lsa [summary-lsa | include-stub | external-lsa | on-startup]
[summary-lsa] Overrides summary-lsa metric with max-metric value
[include-stub] Sets maximum metric for stub links in router-LSAs
[external-lsa] Overrides external-lsa metric with max-metric value
[on-startup] Sets maximum metric temporarily after reboot

### DATABASE OVERLOAD PROTECTION

Controls how many prefixes can be received from a neighbor

redistribute maximum-prefix <max> <thresh%> [warning-only]

[warning-only] When exceeding the maximum number apose to dropping the session

#############################################################################################
### OSPF over FRAME-RELAY

MNEMONIC:
*** NON-BROADCAST = need “neighbor” command.
*** BROADCAST = DR/BDR elected
*** POINT-To-x = No DR/BDR election

### OSPF NON-BROADCAST NETWORKS (H 30s, D 120s)
– Non-Broadcast is the default network type on multipoint frame-relay interface, eg a main interface.

– OSPF routers on NBMA networks elect a DR and BDR, but all OSPF packets are unicast between each manually
specified neighbor with the “neighbor” command.

– The default priority is 1, and should be disabled (=0) on ALL SPOKES, to prevent a spoke from becoming a blackhole DR/BDR.

– The next-hop IP is not changed and remains the IP address of the originating router.
If “inverse-arp” is deactivated, spokes will not have NLRI between eatch other. Configure static mapping (toward the hub) to resolve that issue.

### OSPF BROADCAST NETWORKS (H 10s, D 40s)
– There is NO next-hop modification. The next-hop IP remains that of the originating router.

– Layer3 to layer2 resolution is required.

– Broadcast networks can’t have unicast neighbors configured.

### OSPF POINT-TO-POINT NETWORKS (H 10s, D 40s)
– No DR/BDR election, OSPF configured as per normal.

– The next-hop IP is that of the advertising router.

– OSPF ignores subnet mask mismatch on point-to-point links.

### OSPF POINT-TO-MULTIPOINT NETWORKS (H 30s, D 120s)
– No DR/BDR election

– A host route is created for the IP addresses of all the interfaces connected to the FR cloud

– The next hop IP address of the advertised prefixes is set based on the advertising router and not the router that originated the route.

– CISCO proprietary, best choice for NBMA networks.

### OSPF POINT-TO-MULTIPOINT NON-BROADCAST NETWORKS (H 30s, D 120s)
– Cisco proprietary, the same as point-to-multipoint, but configured with the additional ‘non-broadcast’ keyword.

– Was created to allow for the assignment of the cost per neighbor appose to using the interface’s cost.

– neighbor cost and database-filter options are allowed only for a point-to-multipoint network. That’s why we need to combine P2M and non-broadcast to control cost per-neighbor.

– No DR/BDR election, uses unicast appose to multicast, to each manually specified neighbor.

– As a result the directly connected neighbor must be manually defined with the ‘neighbor’ command. This command is only required on the one side.

– Remember that the cost is based on the ‘incoming’ interface’s bandwidth and not the bandwidth of the neighbor’s interface.

############################################################################################

### MISCELLANEOUS

– Suppress OSPF forwarding address in translated type-5 LSAs

> This is used when an NSSA ABR translates type 7 LSAs to type 5 LSAs, but use the 0.0.0.0 as the forwarding address instead of the address specified in the type 7 LSA.
> Routers which are configured not to advertise forwarding addresses into the backbone, will directly forwarded traffic to the translating NSSA ASBRs.
* area <id> nssa translate type7 suppress-fa [<OPTIONS>]

OPTIONS:

[default-information-originate] –  Originate Type 7 default into NSSA area

[no-redistribution] – No redistribution into this NSSA area

[no-summary] – Do not send summary LSA into NSSA

– Generate default route into a NSSA
* area <id> nssa [default-information-originate] [no-summary]
[default-information-originate] Originate Type 7 default (O*N2) into NSSA area.
[no-summary] Originate Type 3 default (O*IA) into NSSA area. Do not send summary LSA into NSSA.

– When an ABR is also an ASBR and is connected to a NSSA, the default behaviour is to advertise the redistributed routes into the NSSA.
> This redistribution can be turned off by adding the ‘no-redistribution’ keyword to the “area nssa” command.
* area <id> nssa no-redistribution ! No redistribution into this NSSA area

More notes are to come, please leave your comments 🙂

OSPF Filtering

Today we are going to cover a topic that almost sent a DoS to my brain 🙂 some times back: OSPF Filtering. Today, that’s my favorite OSPF topic.

With dynamic routing protocols many prefixes are exchanged. Some are needed in certain location of the network and others are not need or should not be reachable from a given location. It is where filtering comes to help to control the prefixes announcement in the network.

This post will focus on filtering with OSPF.

All over this post we will work with the following topology:

We have area 0 connected to area 1 and area 2 which is NSSA.  R2 redistributes its lo1 IP as External type 1 and R5 redistribute its lo1 IP as external 2 (default).

INITIAL CONFIGURATIONS

 

R1:

interface Loopback0
ip address 10.1.1.1 255.255.255.0
!
interface Loopback1
ip address 10.11.11.11 255.255.255.0
!
interface FastEthernet0/0
ip address 192.168.12.1 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 192.168.13.1 255.255.255.0
duplex auto
speed auto
!
router ospf 1
router-id 10.1.1.1
log-adjacency-changes
network 10.1.1.1 0.0.0.0 area 0
network 10.11.11.11 0.0.0.0 area 1
network 192.168.12.1 0.0.0.0 area 1
network 192.168.13.1 0.0.0.0 area 0

 

R2:

interface Loopback0
ip address 10.2.2.2 255.255.255.0
!
interface Loopback1
ip address 10.22.22.22 255.255.255.0
!
interface FastEthernet0/0
ip address 192.168.12.2 255.255.255.0
duplex auto
speed auto
!
router ospf 1
router-id 10.2.2.2
log-adjacency-changes
redistribute connected metric-type 1 subnets route-map RM_lOOPBACK0->OSPF
network 192.168.12.2 0.0.0.0 area 1
!
!
route-map RM_lOOPBACK0->OSPF permit 10
match interface Loopback1
!

R3:

interface Loopback0
ip address 10.3.3.3 255.255.255.0
!
interface Loopback1
ip address 10.33.33.33 255.255.255.0
!
interface FastEthernet0/0
ip address 192.168.13.3 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 192.168.34.3 255.255.255.0
duplex auto
speed auto
!
router ospf 1
router-id 10.3.3.3
log-adjacency-changes
network 10.3.3.3 0.0.0.0 area 0
network 10.33.33.33 0.0.0.0 area 0
network 192.168.13.3 0.0.0.0 area 0
network 192.168.34.3 0.0.0.0 area 0
!

R4:

interface Loopback0
ip address 10.4.4.4 255.255.255.0
!
interface Loopback1
ip address 10.44.44.44 255.255.255.0
!
interface FastEthernet0/0
ip address 192.168.34.4 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 192.168.45.4 255.255.255.0
duplex auto
speed auto
!
router ospf 1
router-id 10.4.4.4
log-adjacency-changes
area 2 nssa
network 10.4.4.4 0.0.0.0 area 0
network 10.44.44.44 0.0.0.0 area 2
network 192.168.34.4 0.0.0.0 area 0
network 192.168.45.4 0.0.0.0 area 2
!

R5:

interface Loopback0
ip address 10.5.5.5 255.255.255.0
!
interface Loopback1
ip address 10.55.55.55 255.255.255.0
!
interface Loopback2
ip address 10.52.52.52 255.255.255.0
!
interface FastEthernet0/0
ip address 192.168.45.5 255.255.255.0
duplex auto
speed auto
!
router ospf 1
router-id 10.5.5.5
log-adjacency-changes
area 2 nssa
redistribute connected subnets route-map RM_LOOPBACK1->OSPF
network 10.5.5.5 0.0.0.0 area 2
network 192.168.45.5 0.0.0.0 area 2
!
route-map RM_LOOPBACK1->OSPF permit 10
match interface Loopback1 Loopback2
!

OSPF filtering can only occur between areas. As stated in RFC 2328, “Two routers in the same area have, for that area, identical area link-state databases” that is why there is no database filtering inside an area. What is possible is to filter OSPF routes entering the routing table.

In OSPF multiple areas we may need to have control on which routes are sent outside the area and which routes are entering the area. Here comes inter-area filtering.

Before jumping to inter-area filtering, lets see how to filter routes entering to the routing table.

CONTROLING ROUTES ENTERING THE ROUTING TABLE

Let’s take some examples:

– Filter R5 loopback0 IP address (10.5.5.5) from R4 routing table.

On R4 we have 10.5.5.5 as summary LSA in the database and as inter-area route in the routing table.

R4#sh ip ospf data summ 10.5.5.5

           OSPF Router with ID (10.4.4.4) (Process ID 1)

               Summary Net Link States (Area 0)

 LS age: 1759
 Options: (No TOS-capability, DC, Upward)
 LS Type: Summary Links(Network)
 Link State ID: 10.5.5.5 (summary Network Number)
 Advertising Router: 10.4.4.4
 LS Seq Number: 80000002
 Checksum: 0x1FE2
 Length: 28
 Network Mask: /32
       TOS: 0  Metric: 11

R4#sh ip ro 10.5.5.5
Routing entry for 10.5.5.5/32
 Known via "ospf 1", distance 110, metric 11, type intra area
 Last update from 192.168.45.5 on FastEthernet0/1, 00:05:12 ago
 Routing Descriptor Blocks:
 * 192.168.45.5, from 10.5.5.5, 00:05:12 ago, via FastEthernet0/1
     Route metric is 11, traffic share count is 1

To filter a prefix entering the routing table use the following command:

# distribute-list {acl# | acl_name | prefix | route-map} in [interface]

In our case, the configuration below is used on R4:

access-list 1 deny 10.5.5.5 0.0.0.0
access-list 1 permit any
router ospf 1
  distribute-list 1 in

The prefix is not anymore in the routing table.

R4(config-router)#do sh ip ro 10.5.5.5
% Subnet not in table

We can confirm that the prefix is still in the database with the following:

R4(config-router)#do sh ip ospf data summ 10.5.5.5
         OSPF Router with ID (10.4.4.4) (Process ID 1)

             Summary Net Link States (Area 0)

  LS age: 1894
  Options: (No TOS-capability, DC, Upward)
  LS Type: Summary Links(Network)
  Link State ID: 10.5.5.5 (summary Network Number)
  Advertising Router: 10.4.4.4
  LS Seq Number: 80000002
  Checksum: 0x1FE2
  Length: 28
  Network Mask: /32
        TOS: 0  Metric: 11

Let’s check if R3 has the prefix 10.5.5.5 in its Routing table:

R3#sh ip ro 10.5.5.5
Routing entry for 10.5.5.5/32
 Known via "ospf 1", distance 110, metric 21, type inter area
 Last update from 192.168.34.4 on FastEthernet0/1, 01:05:37 ago
 Routing Descriptor Blocks:
 * 192.168.34.4, from 10.4.4.4, 01:05:37 ago, via FastEthernet0/1
     Route metric is 21, traffic share count is 1

R3 is learning the prefix 10.5.5.5/32 through R4, even though this prefix is not present in R4 routing table.

The prefix is filtered from R4 routing table but it is still in the OSPF database, thus sent to other routers.

Keep in mind this has effect only on the router where it is configured on, except if the prefix that is being filtered is coming from area 0, in which case the prefix will be filtered from the database.

INTER-AREA FILTERING

– Filter R1 lo1 address (10.11.11.11) to enter area 2

On R5:

R5#sh ip ro 10.11.11.11
Routing entry for 10.11.11.11/32
 Known via "ospf 1", distance 110, metric 31, type inter area
 Last update from 192.168.45.4 on FastEthernet0/0, 00:30:28 ago
 Routing Descriptor Blocks:
 * 192.168.45.4, from 10.4.4.4, 00:30:28 ago, via FastEthernet0/0
     Route metric is 31, traffic share count is 1

On the ABR R4, we have 10.11.11.11/32 prefix in area 0 and area 2:

R4(config-router)#do sh ip ospf data summ 10.11.11.11
            
			OSPF Router with ID (10.4.4.4) (Process ID 1)

                Summary Net Link States (Area 0)

 Routing Bit Set on this LSA
 LS age: 1724
 Options: (No TOS-capability, DC, Upward)
 LS Type: Summary Links(Network)
 Link State ID: 10.11.11.11 (summary Network Number)
 Advertising Router: 10.1.1.1
 LS Seq Number: 80000003
 Checksum: 0x31D0
 Length: 28
 Network Mask: /32
       TOS: 0  Metric: 1
	   
                Summary Net Link States (Area 2)
 
 LS age: 28
 Options: (No TOS-capability, DC, Upward)
 LS Type: Summary Links(Network)
 Link State ID: 10.11.11.11 (summary Network Number)
 Advertising Router: 10.4.4.4
 LS Seq Number: 80000002
 Checksum: 0x627D
 Length: 28
 Network Mask: /32
       TOS: 0  Metric: 21

The following command is used to filter a prefix from an area, this  should be configured only on the ABR and only works for LSA type 3.

# area <id> filter-list prefix <prefix_name> {in|out}

In our example the configuration below is used on R4:

ip prefix-list PL_R1_LOOPBACK1 deny 10.11.11.11/32
ip prefix-list PL_R1_LOOPBACK1 permit 0.0.0.0/0 le 32

router ospf 1
  area 2 filter-list prefix PL_R1_LOOPBACK1 in

Now the prefix 10.11.11.11/32 is only present in area 0 database, thus it will not appear in R5 routing table.

R4(config-router)#do sh ip ospf data summary 10.11.11.11

            OSPF Router with ID (10.4.4.4) (Process ID 1)

                Summary Net Link States (Area 0)

 Routing Bit Set on this LSA
 LS age: 176
 Options: (No TOS-capability, DC, Upward)
 LS Type: Summary Links(Network)
 Link State ID: 10.11.11.11 (summary Network Number)
 Advertising Router: 10.1.1.1
 LS Seq Number: 80000004
 Checksum: 0x2FD1
 Length: 28
 Network Mask: /32
       TOS: 0  Metric: 1

R5#sh ip ro 10.11.11.11
% Subnet not in table

We could also use the following command to filter LSA type 1, and only type 1, from being injected into a given area.

Example: Filter R3 lo1 IP prefix from being injected  into area 1.

The output below shows that the prefix 10.33.33.33/32 is in Area 0 and Area 1 as LSA type 1 and type 3 respectively.

R1#sh ip ospf data router | inc Area 0 | 10.33.33.33
     (Link ID) Network/subnet number: 10.33.33.33

R1#sh ip ospf data summ 10.33.33.33

           OSPF Router with ID (10.1.1.1) (Process ID 1)

               Summary Net Link States (Area 1)

 LS age: 1671
 Options: (No TOS-capability, DC, Upward)
 LS Type: Summary Links(Network)
 Link State ID: 10.33.33.33 (summary Network Number)
 Advertising Router: 10.1.1.1
 LS Seq Number: 80000004
 Checksum: 0xBAF9
 Length: 28
 Network Mask: /32
       TOS: 0  Metric: 11

Also, R2 sees the prefix through R1:

R2#sh ip ro 10.33.33.33
Routing entry for 10.33.33.33/32
 Known via "ospf 1", distance 110, metric 21, type inter area
 Last update from 192.168.12.1 on FastEthernet0/0, 00:00:02 ago
 Routing Descriptor Blocks:
 * 192.168.12.1, from 10.1.1.1, 00:00:02 ago, via FastEthernet0/0
      Route metric is 21, traffic share count is 1

To filter the prefix to enter area 1, lets configure the following on R1:

router ospf 1
  area 0 range 10.33.33.33 255.255.255.255 not-advertise

Now the prefix is not present in Area 1 database and we can note R2 does not have anymore the route in its routing table.

R1(config-router)#do sh ip ospf data summ 10.33.33.33
           OSPF Router with ID (10.1.1.1) (Process ID 1)

R2#sh ip ro 10.33.33.33
% Subnet not in table
R2#

– Filtering LSA type 5s or 7s from the OSPF database.

We can use distribute-list command with the “out” option on the ASBR only (else it will not have any effect whatsoever) to filter LSA type 5 or 7 from the OSPF database.

Another solution, is to use summary-address command with the option “not-advertise”.

To see how this works, lets filter the prefix 10.22.22.0/24 from the database on R2.

Using distribute-list

We can note that R1 has the prefix in its database as external.

R1(config-router)#do sh ip ospf data ex 10.22.22.0

			OSPF Router with ID (10.1.1.1) (Process ID 1)

                Type-5 AS External Link States

 Routing Bit Set on this LSA
 LS age: 894
 Options: (No TOS-capability, DC)
 LS Type: AS External Link
 Link State ID: 10.22.22.0 (External Network Number )
 Advertising Router: 10.2.2.2
 LS Seq Number: 80000005
 Checksum: 0x597D
 Length: 36
 Network Mask: /24
       Metric Type: 1 (Comparable directly to link state metric)
       TOS: 0
       Metric: 20
       Forward Address: 0.0.0.0
       External Route Tag: 0

On the ASBR, R2, the configuration below is applied:

ip access-list standard AL_R2_LOOPBACK1
  deny 10.22.22.0 0.0.0.255
  permit any
!

router ospf 1
  distribute-list AL_R2_LOOPBACK1 out

The prefix disappeared from R1 database and routing table.

R1(config-router)#do sh ip ospf data ex 10.22.22.0

			OSPF Router with ID (10.1.1.1) (Process ID 1)

R1(config-router)#do sh ip ro 10.22.22.0
% Subnet not in table

Using  summary-address

The previous configuration should be deleted.

On the ASBR, R2, the configuration below is applied:

router ospf 1
  summary-address 10.22.22.0 255.255.255.0 not-advertise

The same effect as the previous section will be noticed.

SUMMARY

For sure this post is not explicit regarding the theory, this latter can be found in the Doc CD or in the links below.

FURTHER READINGS:

OSPF Route Filtering Demystified

OSPF Route Filtering Using Distribute-list

OSPF ABR Type 3 LSA Filtering

My Path: … and one day it started

After being graduated in computer science (in Senegal 2006) I went back home (Mauritania, I know you don’t know where it is) with many programming codes in my head, lol, I was a real geek who doesn’t sleep at all 🙂

I started to work as a programmer for .NET applications and specially working on web services stuffs for MS SharePoint platform.

One day the infrastructure team was planning to re-build the company network. I said myself ok, you did good networking courses at the university you can listen and help them. Seems they have some issues for traffic differentiation at layer 2.

Then I spoke, telling them they just have to use different subnets. lol.

There was a guy who took CCNA courses, he said no we have to create VLAN to separate the traffic and for each type of traffic (or department) we assign a different subnet. That was a shock for me. Then I started to dig deep in my brain trying to remember what virtual LAN means. No results, he tried to explain no way to get what he was talking about, I never practiced in my networking classes, and even never saw a real switch, only 16 port old d-link switches.

The big shock was, when he connected by serial to a 2950 switch and opened hyper terminal (never new what the utility of this software) then started to type some commands. It was like I was dreaming; how come I did not know a switch can be configured (with UNIX-like commands) 😦

I could not sleep well for days. Then I started doing my research about CISCO and CCNA courses. One week later I resigned and went back to Senegal in January 2007 to take CCNA courses. At home, everybody was questioning why why why? No one could understand, know they do.

Its how it started and since I am having fun. I passed the CCNA on March 2008. After that I started to prepare CVOICE, few months later I found it will be hard to get the material to practice for the CCVP.  As I am with BGP MPLS so much at work, I switched for CCIP which I complete at the end of 2009. In June 2010 I completed the CCNP and decided to go for the CCIE R&S which I started to prepare right after.

I started read almost all the recommended books and passed the written in December. And since, I am preparing for the lab which I am planning to sit for in next December in Brussels.

 
 

Hope more fun is ahead 🙂

 
 

Aliou

Hello everyone!

Hi All,

It’s been a while that I wanted to start a blog, but I was always (and still) saying myself can I do it, do I have the time for writing.

How can I know how if don’t make a try?

I started this blog today, and this is the first post. The aim of  this blog, for now, is to relate my journey Toward The Triumph which is to pass the CCIE R&S lab. The posts will be related to CCIE R&S lab topics but sometimes we could have off topic posts.

I hope the language, the time will not be a barrier. 🙂

All your comments and suggestions will be welcome.

Thank you.

Aliou