Stateless and Stateful

• stateless involves a router sending an RA, or router advertisement with a prefix for that link and then the host attaching its MAC address to that to form the IPV6 address.
• stateful simply uses an dhcp server, just like IPV4 does, to allocate addresses.  This is referred to as DHCPv6.

What are these IPV6 addresses?

• 001
• ::1
• ::D190:4E71
• 1111 1111
• FF00::/8
• 1111 1110 10
• 1111 1110 11

• 001 is a global unicast
• ::1 is a loopback
• ::D190:4E71 is an IPV4 compatible address where the first 96 bits are all zeroes.
• 1111:1111 and FF00::/8 are both multicast
• 1111 1110 10 is a link local address used primary on a link for neighbor discovery
• 1111 1110 11 is a site local equivalent to IPV4 private addresses

What are the IPV6 IPs for OSPF's multicast IPV4 addresses for all DR's and BDR's and all OSPF routers?

• 224.0.0.5
• 224.0.0.6

224.0.0.5 is FF02::5

224.0.0.6 is FF02::6

router(config)#ipv6 router ospf 1

router(config-rtr)#router-id 1.1.1.1

If there are no IPV4 addresses on the router, you MUST create a router ID and you must use an IPV4 address-even if you don't have IPV4 address anywhere else on your network.

router(config)#int f0/1

router(config-if)#ipv6 ospf 1 area 3

This will create a router process automatically.  In OSPFv2 you would put an interface in an area in global mode.

What commands gives us this output?

[image]

show ipv6 ospf neighbor or show ip ospf neighbor

Both would give the same output.

rtr(config-if)#int tunnel 0

rtr(config-if)#ipv6 address 2002:DCC8:112A::/48

(need to first convert the IPV4 address to HEX and then create the tunnel interface and apply that new address)

What show command would give you this output?

[image] 

aggregator

community

No, but they do need to be able to reach each others IP address used to create the neighbor relationship.  This is done with the neighbor command under the BGP router process

rtr(config-router)#neighbor 1.1.1.1 remote-as 123

Idle, Connect, Active, Open Sent, Open Confirm, and Established.

Show ip bgp neighbor

The bgp-multihop command.  Example,

rtr(config-router)#neighbor 1.1.1.1 ebgp-multihop 2

* = valid

> = best route

Note: remember if you don't see the asterisk, the route is not usuable.

i = internal

e = external

? = incomplete, usually redistributed

What is wrong with this config?

rtr(config)#int loopback 0

rtr(config-if)#ip address 3.3.3.3 255.255.255.0

rtr(config-if)#router bgp 100

rtr(config-router)#network 3.3.3.3 mask 255.255.255.255

1. Highest Weight

2. Highest Local Preference

3. Whether it originated locally

4. Shortest AS_Path

5. Best origin code

6. Lowest MED

Let's say the route is to 3.3.3.3 that we are concerned with.  Use the command 'show ip bgp 3.3.3.3' to see output that will tell if the route to that device is accessible or not.  Inaccessible routes will give this output:

[image] 

Since router one originally learned the route from router 3, an ebgp peer, and then passed the update to an ibpg peer, router 2, router 1 needs to be the one to announce itself as the next hop.  So, this command would need to go on router 1 aimed at router 2:

rtr1(config-router)#neighbor 2.2.2.2 next-hop-self

MED, the 6th criteria for path selection in BGP, is used to tell an ebgp neighbor the best path by which to ENTER an AS.   Which is odd since its name implies 'exiting' and not entering.  The MED can be set by way of a route map.  Here is one example of creating a route map to set the MED (or metric) to 200.  100 is the default.

rtr(config)#route-map MED permit 10

rtr(config-route-map)#match ip address 1

rtr(config-route-map)#set metric 200

The '1' in the second line is pointing to an access list you much create.

rtr(config)router bgp 100

rtr(config-router)#neighbor 2.2.2.2 weight 200

rtr(config-router)#network 1.1.1.1 mask 255.255.255.0

or

rtr(config-router)#network 1.0.0.0 mask 255.0.0.0

1.  All the routers in the AS are running BGP

2.  Your AS is a full mesh

3.  The AS is not a transit AS

You can turn if off with this command:

rtr(config-router)#no synchronization

Only need to configure router 1, the reflector with these commands:

rtr1(config-router)neighbor 2.2.2.2 route-reflector-client

rtr1(config-router)neighbor 3.3.3.3 route-reflector-client

1.  area number

2.  hello and dead timers

3.  stub flag

Cisco recommends that an area in OSPF not contain more than.

a.  60 routers

b.  100 routers

c.  3 routers

d.  50 routers

You would enter this command at the interface level:

rtr(config-if)ip ospf priority 0

The router with the highest router ID, and here are the rules:

1.  The highest loopback interface is the first address looked at

2.  If not loopback, then the highest address on any physical address is considered

3.  Both of the above can be overridden if a manually configured router ID has been created with the 'router-id X.X.X.X' command under the OSPf routing process

show ip ospf interface X/X

[image]

The neighbor command will need to be used under the routing process for each neighbor.  Example:

rtr(config-router)#neighbor 2.2.2.2

This command will not be needed on the spoke routers

The hello and dead timers on a broadcast OSPF network, like ethernet, is 30 and 120 respectively.

T  or  F

NBMA, but it can be changed with the 'ip ospf network XXXXX' command. The four choices are:

broadcast

non-broadcast

point-to-multipoint

point-to-point

If you don't put anything it will default to broadcast, but you can make it nonbroadcast with the 'nonbroadcast' parameter.

rtr(config-if)ip ospf network point-to-multipoint non-broadcast

Just remember that if you choose non-broadcast you will have to statically configure neighbors

What two network types in OSPF are RFC compliant from this list:

NBMA

point-to-multipoint

broadcast

point-to-point

point-to-multipoint nonbroadcast

NBMA and point-to-multipoint

The others are not officially compliant but can be used over a NBMA network.

1.  Used wrong IP in command.  Have to use the remote routers RID

2.  Forgot to configure authentification when area 0 is doing it

3.  Tried to use a stub area as the transit area

The OSPF command to create a virtual link is entered in what router config mode?

Global, interface, or router

64.  Others are:

Ethernet          10

FastEthernet      1

56k circuit     1785

What are OSPF's 8 stages to neighbor adjacency?

1.  Down

2.  Attempt - hello packets sent

3.  Init - hello packet received

4.  2-Way - hello received with each router's own RID meaning 2-way communication is established

5.  Exstart - DR/BDR election and master/slave relationship set up and databases starting to be shared

6.  Exchange - DBD packets exchanges with Link State Database info

7.  Loading - sending of LSR's to each other

8.  Full - each router's Link State Database are synchronized with each other