Problems in OSPF learning

OSPF docking two parties, the requirements on the setting, which parameters must be the same

(HELLO &dead interval, area ID, authentation, Stub region (e-bit in option), network mask)

The e-bit in the distal area is 0, this bit is not the same, the adjacency relationship cannot be established

Hello interval and Hello timer difference (timer initial value is interval, when timeout, send hello)

On Dr Others, Show OSPF neighbor, can see other Dr others (can see, know how many routers on the network, but only with the DR, BDR to establish the adjacency relationship, see routing TCP/IP, how does he know how many routers on the network? Dr's network LSA),

received Hello, send a response now?

P 286 difference stub network and stub area

The selection process of DR and BDR qualification? , Dr is just in the peripheral area? 0area also has DR, all areas have Dr

When a router joins the network, if the original is already stable, the presence of Dr and BDR, how does this new router know that the routers in the network that are not DR and BDR are not going back to this router's hello?

Dr Selection is complete, and when new router with higher priority are added, they can only be used as router others

The process of starting OSPF will wait for a period of time, if you do not start the other routers, the first one thinks that he is Dr, this wait time is called the waiting timer timer, the Cisco prescribed wait timer is generally 40s. This time to start the router to participate in the selection, the real environment, 40S, generally only launched two, Dr will be in between the first two, after a period of work, the most likely to live the longest router is Dr.

When do I send LSA?

The following four lists per neighor each neighbor one?

Database Summary List

Database Description Data Packet description packet, (as if only Dr sent Others, Dr---> Route others,dr Control Database Description synchronization, see Routing TCP/IP, How did Dr know that the network was hung under others? ), just the LSA header. The head of all LSA

Link status request list) Link State requests list (received update, request linked list is reduced), each send several requests? When did you send it?

Link status Update link state update (How many updates are received each time?) )

Link state information Base

Link State retransmission List

Hello establishes both communication, database description,

1) Negotiate dr/dr others.

2) database description, Exchange LSA, just Dr sent to router Others?

DR send DD to others, one LSA at a time? Others also has this LSA header in the reply to Dr?

After negotiating the dr/routers, why did Dr Send request requests in the database?

P304 , why is the second DD, in the response sent by oothers, labeled flag 0x00,m bit not set?

The originating router of the LSA can age LSA

How is the latest LSA?

1 Maximum serial number

IF The serial number is the same, the maximum checksum

IF The serial number is the same, the checksum is the same maximum aging time

IF aging Time >15min, the LSA of the minimum aging time is up to date.

If the above cannot be judged, think the same

When a router joins the network, if the original is already stable, the presence of Dr and BDR, how does this new router know that the routers in the network that are not DR and BDR are not going back to this router's hello?

What is flooding?

(When the link state sends changes, update and acknowledge, can be sent multiple at a time, each individual transmitted LSA must be confirmed, sent and confirmed with a multicast address?) ）

when flooding, what kind of LSA is sent? What kind of need to forward? Update and acknowledge

Each separately transmitted LSA must be confirmed, sent and confirmed with a multicast address? How is unicast confirmation confirmed?

Show acknowledgement: Send LSA acknowledgement packet

Implicit acknowledgment: Sends an update packet that contains the LSA copy information

Direct acknowledgement: Send unicast response

P308 Router receives an LSA that is not in the link state repository, why should I confirm it?

P308 when do I need to generate a new instance for the LSA (new instance), after the LSA reaches the aging time, it needs to flood again ?  Why would you want to remove this LSA from the database ? When will a new instance of Las be generated ?

What is recorded in the database?

P315 virtual link, there is also a virtual link in the Ethernet router?

P317 link re-brush mechanism

Type Code	Description
1	Hello
2	Database Description
3	Linkstate Request
4	Linkstate Update
5	Linkstate Acknowledgment

DR/BDR is only in the peripheral area?

Is Dr an ABR?

P322 ABR How to choose the lowest cost LSA, multiple LSA arrived, if first arrived LSA is not optimal, the ABR should not broadcast

As the external LSA floods within the autonomous system, but does not include the peripheral area, the peripheral Dr sends a network summary 0.0.0.0 default route in the peripheral area, all external packets, from the ABR to the external

In the peripheral area, the Router others has all the routes within the as autonomous domain and a default route to the ABR

The network rollup LSA and the ASBR rollup LSA are the routes that advertise the outside of the internal router, or the internal route to the external router

There are multiple ABR in the peripheral area, but a Dr? How is ABR configured?

ABR ASBR, what type of LSA does DR drothers send separately?

Route redistribution. How do external routes import OSPF domains?

How the routing table---forwarding

Token Ring, FDDI?

Uniquely identifies an LSA: type, link state, and advertisement router

Identify the latest LSA: Aging time, serial number, checksum

Equivalent routing Policy Routing Is-is

Virtual link must be configured on the ABR, why

What is the convergence rate of OSPF? Rip?

Http://support.huawei.com/ecommunity/bbs/10144223.html

0.0.0 . 0 255.255.255.255 area 1 All interfaces

Why is 0.0.0.0?

P349. Why is the mask on Goya 0.0.0.3 and 0.0.0.31?

P353 Why the main net deleted, subnet also no longer notice?

P355 static routes have no category, what is the category of routing?

P356 Route Redistribution

P357 Rubens See other area ABR? But you can see all the ASBR, no matter what the ASBR is not in this area.

In the peripheral area, the Router others has all the routes within the as autonomous domain and a default route to the ABR

Full peripheral area, only routing and default routes within the region

P368

Route black holes and route loops, pointing to the null port

RFC2328 P82 one DD at a time? How does Dr know the connection state of the router below, even the following subnet?

Figure 7 of the database, RT4 how to area1 broadcast Summary-lsa, those need to converge? N9 n0 H1, N6 n7 N8 Why not synthesize one?

Is Dr the same as the other router Router_lsa?

P112 RT3 in AREA1 broadcast Router-lsa do not need to be able to connect to 18. Network?

AREA0 also have Dr and Bdr, other drothers?

How does OSPF avoid loops?

Why does OSPF converge fast?

Virtual link, non-broadcast link

internal OSPF autonomous system, based on link state and SPF

How equivalent routes load-sharing

PROBLEM2:

Three sheets: Neigbors network topology Table routing table

RFC2328 P93

, the slave must wait routerdeadinterval seconds to release the last DD package. After this, the Seqnumbermismatch neighbor event is generated when the DD packet is received.

RFC2328

Why is the cost of Figure7 RT3 to RT5 been RT6 14 instead of 10 by RT4?

Figure 6 RT3 and RT4 no direct connection?

OSPF docking two parties, the requirements on the setting, which parameters must be the same

(HELLO &dead interval, area ID, authentation, stub zone, network mask)

Hello interval and Hello timer difference (timer initial value is interval, when timeout, send hello)

On Dr Others, Show OSPF neighbor, can see other Dr Others (should not see, because Dr others only and Dr, bdr establish connection relationship),

Receive Hello and send a response now?

P 286 difference stub network and stub area

The selection process of DR and BDR qualification? , Dr is just in the peripheral area?

When a router joins the network, if the original is already stable, the presence of Dr and BDR, how does this new router know that the routers in the network that are not DR and BDR are not going back to this router's hello?

Dr selected, when the new higher priority router added, can only be used as router others to avoid shocks,

When do I send LSA?

The following four lists per neighor each neighbor one?

Database Summary List

Database Description Data Packet description packet, (as if only Dr sent Others, pending confirmation, Dr---> Route others,dr Control Database Description synchronization), just the LSA header. The head of all LSA

Link status request list) Link State requests list (received update, request linked list is reduced), each send several requests? When did you send it?

Link status Update link state update (How many updates are received each time?) )

Link state information Base

Link State retransmission List

Hello establishes both communication, database description,

1) Negotiate dr/dr others.

2) database description, Exchange LSA, just Dr sent to router Others? Border routers

DR sends DD to others, one LSA at a time? Others also has this LSA header in the reply to Dr?

After negotiating the dr/routers, why did Dr Send request requests in the database?

P304, why is the second DD, Oothers sent in response, labeled flag 0x00,m bit not set?

How is the latest LSA?

DR/BDR is only in the peripheral area?

When a router joins the network, if the original is already stable, the presence of Dr and BDR, how does this new router know that the routers in the network that are not DR and BDR are not going back to this router's hello?

What is flooding?

(When the link state sends changes, update and acknowledge, can be sent multiple at a time, each individual transmitted LSA must be confirmed, sent and confirmed with a multicast address?) ）

Each separately transmitted LSA must be confirmed, sent and confirmed with a multicast address? Flooding in non-core areas, is other router issued to DR,DR to other router, or routers directly to all router?

Show acknowledgement: Send LSA acknowledgement packet

Implicit acknowledgment: Sends an update packet that contains the LSA copy information

Direct acknowledgement: Send unicast response

P308 Router receives an LSA that is not in the link state repository, why should I confirm it?

P308 when do I need to generate a new instance for the LSA (new instance), after the LSA reaches the aging time, it needs to flood again?  Why would you want to remove this LSA from the database? When will a new instance of Las be generated?

What is recorded in the database?

P315 virtual link, there is also a virtual link in the Ethernet router?

When virtual channels are configured for virtual channels

Virtual link is a link that connects to a backbone area through a non-backbone area.

When configuring a virtual link, there are a few related rules,

Virtual link must be configured between two ABR routers

The region that is configured with the virtual link must have all of the routing information, which is also known as the transfer Zone (Transit area) Delivery region cannot be a peripheral area, why?

P317 link re-brush mechanism

Periodic updates

How external routes import OSPF domains

How the routing table---forwarding

Token Ring, FDDI?

Equivalent routing

The network rollup LSA and the ASBR rollup LSA are the routes that advertise the outside of the internal router, or the internal route to the external router

Virtual link must be configured on the ABR, why

What is the convergence rate of OSPF? Rip?

5 Types of LSA, content

Router LSA RFC P112

When the content described by the LSA changes, a new LSA is generated. However, two instances of the same LSA cannot be generated consecutively within the time Minlsinterval

Router-lsa, how to differentiate between point-to, broadcast, stub, virtual channel?

RFC 2328 P119 RT3 in area1 Why do you want to notify the stub network 1.4.0

Why should I set e-bit in P121 Network-lsa?

Network-lsa Router-lsa

Link-type should distinguish between router, or network summary external-

Http://support.huawei.com/ecommunity/bbs/10144223.html

Problems in OSPF learning