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قديم 12-02-2010, 10:45 AM   #13
elbass
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تاريخ التسجيل: Jul 2010
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elbass will become famous soon enough
افتراضي رد: دورة ccda للمهندس رامى كاملة

مقدمة
السلام عليكم
بداية وجب التنويه المهم جداً على أن هذا الفصل يعتبر من أهم الفصول في منهج الدورة وذلك لأهميته التطبيقية من الناحية العملية فهو يتحدث باسهاب عن بروتوكولات مسارات التوجيه وماهي الفروق التي بينهم وأين استخدام كل واحد منهم.


الفهرس

Static versus Dynamic

Distance Vector versus Link state

Interior versus Exterior

Hierarchal versus Flat



Static versus Dynamic

ومن أشهر أماكن استخدام التوجيه الثابت في الأماكن التالية:
Routing to and from a stub network
Small network
Special feature: such as dial on demand routing

السؤال
Name at least two cases where static routing is appropriate within a network design.
Static routing is appropriate in the following cases:
الجواب
- The network is small and not complex; the network also has a very slow rate of expansion or change.
- The network consists of a main larger network with one or more stub networks.
- The network should include special features, such as dial-on-demand routing.

You are considering using static routes in a stub area configuration with a network. What are two advantages that exist through the use of a static route in this design?
By using a static route with a stub network, the following advantage exist:

- Dynamic routing protocol control information is not used on the link to the stub, or in the stub network; this reduces the amount of routing protocol traffic the network must carry
- Smaller routing tables are present in routers with the stub and central networks
- Low end routers can be used in the stub network
- Processor requirements for routers are lower



Distance Vector versus Link state
أمثلة على
Distance Vector
RIPv1, RIPv2, IGRP
من مميزات على النوع من التصنيف

Entire Routing tables are transferred periodically between the systems
جداول التوجيه تحدث بشكل دوري بين أنظمة الشبكة

Trend to converge slowly
الوقت التغيري بطىء نوعا ما

Offer limited scalability
التطورية محدودة لديه

Easy to implement and maintain
سهولة التركيب والصيانة

Which of the following routing protocols are considered distance vector?
- EIGRP
- OSPF
- IS-IS
- BGP
- RIP v1
- IGRP
- RIP v2
BGP, RIP v1 and V2, and IGRP are all considered distance vector routing protocols. EIGRP is considered a hybrid routing protocol.
الموضوع الأصلى من هنا: منتديات سيسكو التعليمية | كن بين الخبراء ! http://www.ciscovb.com/vb/2119-post15207.html


Because it is a routing protocol that features the best of distance vector mechanisms and the best of link state mechanisms, it is often considered a hybrid routing protocol. Which is it?
EIGRP offers the best features of both types of protocols and, as a result, is often considered a hybrid routing protocol.

Link state

أمثلة عليه
OSPF, IS-IS

Each router makes routing decisions based on local database
كل موجه له قراره المستقل بالاعتماد على قاعدة البيانات الموجودة في الشبكة

Faster Convergence
الوقت التغيري سريع

Better Scalability
إذا ما قورنت مع النوع السابق

Feature less routing traffic overhead
وهذه من أهم مميزاته أن رأس المعلومات يحتوي على أقل معلومات وبالتالي يكوت أفضل وأسرع

Requires more knowledge and expertise to configure
معلومات أكثر ويحتاج إلى خبراء
السؤال
What algorithm does a link state routing protocol use to select the best path to a destination?
الجواب
The common shortest path first, or Dijkstra's algorithm, is used.

What is the most common Exterior Gateway Protocol in use today, and what is its function?
BGP version 4 powers the routing functions of the Internet as we know it today. BGP+ takes over once IPv6 is fully deployed. BGP is responsible for routing between separate Autonomous Systems.



السؤال
What default metrics does EIGRP use?
الجواب
The default metrics used by EIGRP are bandwidth and delay.
السؤال
What is the default metric used by OSPF? From what is this value derived, by default?
الجواب
The default metric used by OSPF is cost. By default, this metric is derived from bandwidth.
السؤال
What default metric does RIP use?
الجواب
The default metric used by RIP is hop count.
السؤال
Which type of routing protocol converges faster: distance vector or link state? Why?
الجواب
Link state routing protocols converge faster than distance vector protocols because they instantly propagate route updates, while distance vector technologies rely on a periodic update. This statement remains true when the distance vector routing protocols use their default timers, of course.







Interior Gateway Protocol – IGPs
من الأمثلة عليها
OSPF, IS-IS, EIGRP, RIP

These routing protocol handle the dynamic routing that occurs within the private network
وبالتالي يكون استخدامها داخلي في الشبكة الخاصة بالمنشأة

Fast convergence and easier configuration
تتمتع بالسرعة والسهولة



Exterior Gateway Protocol – EGPs
من الأمثلة عليها : BGP

They handle routing between the autonomous system
أماكن تواجدها

Slower convergence and more complex configuration
بطيئة ومعقدة التهيئة

Routing protocol metrics
وهي العوامل التي تؤثر على بروتوكولات مسارات التوجيه
RIP-Hop account
IGRP-Bandwidth and delay
EIGRP-Bandwidth-delay
BGP-Path
OSPF-Cost (bandwidth)
IS-IS, Link metrics


Hierarchal Routing Protocol

Examples are classless

Divide the network into area; they don’t propagate information throughout the entire network –area are used instead
الفكرة أن عملية نشر المعلومات لا تتم على كامل الشبكة وإنما على أجزاء وأجزاء
They are scalable
قياسية

Flat Routing Protocol

Examples are classful routing protocol

They are not scalable
ليست قياسية

السؤال
What is the main difference between a classful routing protocol and a classless routing protocol?
الجواب
A classful routing protocol does not send the subnet mask information with routing updates. A classless routing protocol includes this information.


أما الآن فسأترككم مع لمحة سريعة لكل من مسارات التوجيه كنبذة بسيطة عنه

RIPv2
RIPv2 is a classless version of RIP (VLSM supported).it uses multicast rather than broadcast to propagate routing information. However, the hop count limitation is 15

EIGRP
A hybrid routing protocol ,EIGRP uses the same metric as IGRP by multiplies it by 256 to allow for greater flexibility .EIGRP is a classless (supported VLSM) .EIGRP uses the diffusing update algorithm(DUAL) to maintain fast convergence

OSPF
OSPF is an extremely scalable link state routing protocol that also features excellent convergence .OSPF uses a cost metric that is based on bandwidth

Integrated IS-IS
Integrated IS-IS supports OSI and IP networks and can do simultaneously. Simple area design presents advantages over OSPF

BGP
BGP is exterior routing protocol that is used to route on the internet .it is a distance vector with many enchantments and allows administrator to heavily influence routing decision to permit “strategic routing policies”









السؤال
Describe Variable Length Subnet Masking.
الجواب
Variable length subnet masking allows the administrator to assign different subnet masks to different parts of the network. This allows for more efficient use of available IP address space, and for more hierarchical-based network designs. As a result, summarization can be performed, and more efficient dynamic routing is achieved.
السؤال
Which type of routing supports VSLM: classful or classless?
الجواب
Classless routing protocols support VLSM.

السؤال
Which of the following routing protocols are classless routing protocols?
الجواب
- IGRP (Interior Gateway Routing Protocol)
- EIGRP
- RIP v1 (Routing Information Protocol)
- RIP v2 (Routing Information Protocol)
- OSPF
- BGP (Border Gateway Protocol)
- IS-IS
EIGRP, RIP v2, OSPF, BGP and IS-IS are all classless routing protocols.

السؤال
Name at least two aspects/advantages of on-demand routing (ODR).
الجواب
On-demand routing has the following characteristics/advantages:

- Reduces dynamic routing traffic overhead
- Ideal for hub and spoke topologies
- No IP routing protocol on the stub networks is required
- ODR relies upon CDP
السؤال
What is the metric, and what is the metric limit with RIP v2?
الجواب
RIP v2 uses hop count as a metric. The hop count limit is 15.
السؤال
Name at least two advantages that RIP v2 has over its RIP v1 counterpart.


الجواب


The following advantages exist:

- VLSM support
- Multicast, instead of broadcast
- Faster convergence
- Manual route summarization
- Authentication

السؤال
Which dynamic routing protocol offers built-in support for routing IP and OSI protocols?
الجواب
The IS-IS protocol can do both. It is called Integrated IS-IS when it is used for routing TCP/IP traffic.
السؤال
When BGP is running between routers in a single autonomous system, what is it called?
الجواب

iBGP, or Interior BGP.

__________________

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الجاهل يُعلّم و صاحب الهوى ليس لنا عليه سبيل

التعديل الأخير تم بواسطة elbass ; 12-02-2010 الساعة 11:39 AM
elbass غير متواجد حالياً   رد مع اقتباس
 

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