Quick Notes - MPLS and OSPF

You must enable MPLS but you cannot enable "mpls ip" on the interface. Current network is leveraging OSPF.

R1

interface Serial1/0
 ip address 192.168.0.1 255.255.255.0
interface Serial1/1
 ip address 192.168.2.1 255.255.255.0

router ospf 1
 mpls ldp sync (this ensures that MPLS waits for the IGP to be fully synchronized before issuing labels - not required for the configuration)
 mpls ldp autoconfig area 0 (this enables MPLS on all interfaces that are in area 0)
 log-adjacency-changes
 network 0.0.0.0 255.255.255.255 area 0

R2

interface Serial1/0

 ip address 192.168.0.2 255.255.255.0

interface Serial1/1

 ip address 192.168.2.2 255.255.255.

router ospf 1
 mpls ldp sync
 mpls ldp autoconfig
 log-adjacency-changes
 network 0.0.0.0 255.255.255.255 area 0

MPLS Scenario

Here is a drawing I put together for MPLS - I was going to configure the scenario and create some troubleshooting scenarios but I have now decided to post it first and let everyone create a working solution.

Once everyone has a chance to create a working solution I will start asking "what ifs"

Feel free to post your solutions

Note: You will not be able to post the entire configuration as I believe there is a limit to the number of characters you can post in the comment field. You can approach it 2 ways

1. you can email me the solution and I will find a way to post it so everyone can leverage the particular scenario
2. you can break the solution up by technology. ex: BGP then post MPLS then.......

packets.analyzed@gmail.com

Let me know if this helps with your studies

Quick Notes - OSPF Authentication

OSPF Authentication

-Null, Type 0
-Clear Text, Type 1
-MD5, Type 2
keyid - is used as part of the equation to come up with the MD5 hash, Keyid must be the same on both sides

Note: Ensure that you authenticate virtual links when enabling authentication in area 0

Clear Text

-Under router ospf, "area # authentication"
-Under the interface, "ip ospf authentication-key [password]"

show ip ospf 1 interface
Serial1/2 is up, line protocol is up
  Internet Address 192.168.0.11/24, Area 0
  Process ID 1, Router ID 192.168.0.11, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:00
  Supports Link-local Signaling (LLS)
  Index 1/1, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 192.168.0.14
  Suppress hello for 0 neighbor(s)
  Simple password authentication enabled


MD5

-Under router ospf, "area 0 authentication message-digest"
-Under the interface, "ip ospf message-digest-key 1 md5 [password]"


do show ip ospf interface
Serial1/2 is up, line protocol is up
  Internet Address 192.168.0.11/24, Area 0
  Process ID 1, Router ID 192.168.0.11, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:05
  Supports Link-local Signaling (LLS)
  Index 1/1, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 192.168.0.14
  Suppress hello for 0 neighbor(s)
 Message digest authentication enabled
    Youngest key id is 1

Quick Notes - OSPF LSA Types

LSA Types

Type 1 - Router
Type 2 - Network
Type 3 - Network Summary
Type 4 - ASBR Summary
Type 5 - AS External
Type 7 - NSSA External

Router LSA Type 1 - Includes a list of all routers links and their states. Flooded in the area they are originated in

Network LSA Type 2 - DR produces these LSA on every multi-access network.Includes all routers including the DR. Flooded in the area they are originated in.

Network Summary LSA Type 3 - Generated by ABR and advertises destinations outside of the area. Flooded throughout the AS

ASBR Summary LSA Type 4 - Generated by the ABR, provides a gateway to type 5 LSA. Flooded throughout the AS

AS External LSA Type 5 - Generated bt ASBR, advertises external destinations or a default route to a external destination. Flooded throughout the AS

NSSA External LSA Type 7 - Generated by ASBR in a not-so-stubby area

Troubleshooting 4

The routing table on R3 should be able to reach 192.168.1.0/24 through 192.168.2.2 and not through 192.168.3.5.

Restrictions: You cannot modify administrative distance or do any type of filtering. The network192.168.1.0/24 must be advertised on R2 in both OSPF and BGP. You must ensure that R2 and R3 are not sending OSPF advertisements to R5. R5 can only use BGP as its routing protocol and must advertise its loopback.

Question 136

When doing "debug ip ospf packets" what do the following fields mean?


OSPF: rcv. v:2 t:1 l:48 rid:10.1.1.1
      aid:0.0.0.0 chk:3437 aut:0 auk: from 
serial 0/1

Question 135

What is the difference between "area # range" and "summary-address" ?

Troubleshooting 1

Determine what the issue/issues in the configuration below. Lab it up!


R1
__
interface loopback 0
 ip address 1.1.1.1 255.255.255.255
interface serial 1/0
 encapsulation frame-relay
 ip address 192.168.1.1 255.255.255.0
 frame-relay map ip 192.168.1.2 102 broadcast
 frame-relay map ip 192.168.1.3 103 broadcast
 ip ospf network-type point-to-multipoint

router ospf 1
 network 192.168.1.1 0.0.0.0 area 0
 network 1.1.1.1 0.0.0.0 area 0


R2
__
interface loopback 0
 ip address 2.2.2.2  255.255.255.255
interface serial 1/0
 encapsulation frame-relay
 ip address 192.168.1.2 255.255.255.252
 frame-relay map ip 192.168.1.1 201 broadcast
 frame-relay map ip 192.168.1.3 201
 ip ospf network-type point-to-multipoint

router ospf 1
 network 192.168.1.2 0.0.0.0 area 0
 network 2.2.2.2 0.0.0.0 area 0

R3
__
interface loopback 0
 ip address 3.3.3.3 255.255.255.255
interface serial 1/0
 encapsulation frame-relay
 ip address 192.168.1.3 255.255.255.0
 frame-relay map ip 192.168.1.2 301 broadcast
 frame-relay map ip 192.168.1.1 301 broadcast

router ospf 1
 network 192.168.1.3 0.0.0.0 area 0
 network 3.3.3.3 0.0.0.0 area 0

Question 134

How would you connect noncontiguous area's to area 0 ? You cannot use a virtual-link.

Question 133

How would you connect noncontiguous area's to area 0 ? You cannot use a tunnel interfaces.

OSPF Superbackbone and Shamlinks

Want to understand more about MPLS-VPN and OSPF superbackbone and shamlinks then check out the link below

Superbackbone and Shamlinks

Question 77

What are the LSA types supported?

Describe each of them.

Question 76

What are the OSPF network types?

Explain whether they require DR/BDR, use multicast, need the neighbor command, and specify the timers.

Question 75

What network type is used with unicast but elects and DR and BDR?

Question 74

What LSA's are allowed in a Stub Area, Totally Stubby Area, NSSA, Totally NSSA.

Question 1

How do you correctly advertise the loopback interface into OSPF using the correct mask?

Interface loopback address is 1.0.0.1/24