Maintains a routing table

CCNA 1 AND 2 COMPANION GUIDE REVISED CISCO NETWORKING ACADEMY PROGRAM PART 75 DOC

Distance Vector Routing 713 Load Balancing Across Multiple Paths Load balancing describes the capability of a router to transmit packets to a destination IP address over multiple paths. Load balancing is a concept that allows a router to take advantage of multiple paths to a given destination. The paths are derived either stati- cally or with dynamic protocols, such as RIP, Enhanced IGRP (EIGRP), Open Shortest Path First (OSPF), and IGRP. Figure 16-2 shows an example of load balancing. When a router learns of multiple routes to a speciﬁc network through multiple routing processes or routing protocols, it installs the route with the lowest administrative dis- tance into the routing table. Sometimes, the router must choose from many routes pro- vided by the same routing process with the same administrative distance. In this case, the router chooses the path with the lowest cost or metric to the destination. Each routing process calculates its cost differently, and the costs might need to be manually conﬁgured to achieve load balancing.

10

INTRODUCTION TO THE CARDIOVASCULAR SYSTEM PART 8 POT

Body posture also influences how the car- diovascular system responds to exercise be- cause of the effects of gravity on venous re- turn and central venous pressure (see Chapter 5). When a person exercises in the supine po- sition (e.g., swimming), central venous pres- sure is higher than when the person is exercis- ing in the upright position (e.g., running). In the resting state before the physical activity begins, ventricular stroke volume is higher in the supine position than in the upright posi- tion owing to increased right ventricular pre- load. Furthermore, the resting heart rate is lower in the supine position. When exercise commences in the supine position, the stroke volume cannot be increased appreciably by the Frank-Starling mechanism because the high resting preload reduces the reserve ca- pacity of the ventricle to increase its end- diastolic volume. Stroke volume still increases during exercise although not as much as when exercising while standing; however, the in- creased stroke volume is resulting primarily from increases in inotropy and ejection frac- tion with minimal contribution from the Frank-Starling mechanism. Because heart

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CCNA 1 AND 2 COMPANION GUIDE REVISED CISCO NETWORKING ACADEMY PROGRAM PART 77 PDF

■ Hop count is used as the metric for path selection (see Figure 16-11). ■ If the hop count is greater than 15, the packet is discarded. ■ By default, routing updates are broadcast every 30 seconds. Note in Figure 16-11 that the 19.2-kbps path between the two hosts using the top routers is 2 hops. The lower alternate path using the three T-1 links is 4 hops. Because RIP path selection is based solely on the number of hops, in this case, RIP path selection chooses the 19.2-kbps link instead of the much faster T1 links.

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Module 2-3 – Implementing and Verifying EIGRP pptx

When you configure the ip default-network command, a static route (the ip route command) is generated in the router configuration. However, the Cisco IOS software does not display a message to indicate this. The entry appears as a static route in the routing table of the router in which the command is configured, as can be seen in the router A configuration and routing table in the figure. This entry can be confusing if you want to remove the default network. The configuration must be removed with the no ip default-network

26

THE COMPLETE IS-IS ROUTING PROTOCOL- P29 PPT

Both implementations result in a list of preﬁxes that need to change in the main routing table.. After that, the router updates the forwarding state in the forwarding plane.[r]

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TỐI ƯU HÓA VIỄN THÔNG VÀ THÍCH NGHI KỸ THUẬT HEURISTIC P9 DOC

Figure 9.8 Load status of links (RIP). In the routing information protocol, a path such as 11 ⇒ 13 ⇒ 18 becomes extremely heavily loaded. On the other hand, a path such as 11 ⇒ 12 ⇒ 15 ⇒ 16 ⇒ 17 ⇒ 18, which is an alternative to 11 ⇒ 13 ⇒ 18, is not frequently used at all; therefore, links for this more roundabout path are lightly loaded. By employing the shortest-path first protocol, we can slightly reduce the load on the links. For the adaptive shortest path first protocol, the majority of the links become heavily loaded because of the frequently broadcast messages to observe the communication latency of all links. On the other hand, the GARA can greatly reduce the load of links, especially on heavily loaded ones. This is not only because the GARA algorithm calculates paths which minimize communication latency with less communication overhead, but also because it distributes packets among alternative paths in the routing table which avoids heavily loaded links.

16

Routing

Adding the permanent keyword to a static route statement will keep the static routes in the routing table even if the interface goes down and the directly connected networks are removed. You cannot get to these routes—the interface is down—but the routes remain in the table. The advantage to this is that when the interface comes back up, the static routes do not need to be reprocessed and placed back into the routing table, thus saving time and processing power.

36

ĐỊNH TUYẾN MULTICAST ROUTING

Multicast Routing Alg.s and Prot.s (Cont’s) • RPF and Prunes When the first packet in a multicast transmission reaches the end leaves in the routing tree, the leaf router sends a pruning message upstream if it does not have any group members attached to it. Likewise, if a any

40

THE ILLUSTRATED NETWORK P48 PDF

Of course, one major legacy of the Internet bubble was the underutilization of fi ber optic links with more than 45 Mbps, and in many cases greatly in excess of 622 Mbps. And digital video could produce stunning images with less and less band- width as time went on. And in that world, in many cases, ATM was left as a solution without a problem. ATM did not suffer from lack of supporters, but it proved to be the wrong technology to carry forward as a switching technology for IP networks.

10

INTERNETWORKING WITH TCP IP P18 POT

In practice, accurate estimation of round-trip delay can be difficult and substantial- ly restricts the utility of ICMP timestamp messages. Of course, to obtain an accurate estimate of round trip delay, one must take many measurements and average them. However, the round-trip delay between a pair of machines that connect to a large inter- net can vary dramatically, even over short periods of time. Furthermore, recall that be- cause IP is a best-effort technology, datagrams can be dropped, delayed, or delivered out of order. Thus, merely taking many measurements may not guarantee consistency; sophisticated statistical analysis is needed to produce precise estimates.

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INTERNETWORKING WITH TCP IP P39 PDF

Thus, the datagram must pass through six routers. However, the optimal (i.e., shortest) path from X to Y only contains two routers (R, and R,). PIM sparse mode includes a facility to allow a router to choose between the shared tree or a shorest path tree to the source (sometimes called a source tree). Although switching trees is conceptually straightforward, many details complicate the protocol. For example, most implementations use the receipt of traffic to trigger the change - if the traffic from a particular source exceeds a preset threshold, the router begins to estab- lish a shortest path?. Unfortunately, traffic can change rapidly, so routers must apply hysteresis to prevent oscillations. Furthermore, the change requires routers along the shortest path to cooperate; all routers must agree to forward datagrams for the group. Interestingly, because the change affects only a single source, a router must continue its connection to the shared tree so it can continue to receive from other sources. More im- portant, it must keep sufficient routing information to avoid forwarding multiple copies of each datagram from a (group, source) pair for which a shortest path tree has been es- tablished.

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Tối ưu hóa viễn thông và thích nghi Kỹ thuật Heuristic P8 doc

Virtually all packet-switched networks base their routing decisions using some form of least-cost criterion. This criterion may be, for example, to minimise the number of hops, or to minimise packet delay. Two elegant algorithms in widespread use in both centralised and distributed form, are those of Dijkstra (1959) and Ford and Fulkerson (1962), both of which translate to shortest-path routing algorithms in the communication network context. We now briefly discuss the development of the USA ARPANET packet-switched network, since the problems encountered, and solutions to these problems, exemplify the difficulties of adaptive, distributed routing techniques. The ARPANET is also significant since it formed the initial basis from which the current world wide ‘Internet’ has evolved.

14

CCNA 1 AND 2 COMPANION GUIDE, REVISED (CISCO NETWORKING ACADEMY PROGRAM) PART 74 PPTX

link-state routing protocol A routing algorithm in which each router broadcasts or multicasts information regarding the cost of reaching each of its neighbors to all nodes in the internetwork. Link-state algorithms create a consistent view of the network and are therefore not prone to routing loops. However, they achieve this at the cost of rela- tively greater computational difﬁculty and more widespread trafﬁc than do distance vector routing algorithms.

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Handbooks Programming Support CiS# - Language CiS# part 1Handbooks Programming Support CiS# - Language CiS# part 20 ppsx

Giả sử rằng subnet 192.168.3.1/27 trở thành không tới được. Podres có thể forward (chuyển tiếp) packet có địa chỉ đích thuộc subnet 192.168.3.128/125 một cách không rõ ràng. Packet được gửi vào OSPF domain nơi mà bạn mong muốn tuyến đường tóm lược sẽ mang packet trở lại Podres. Kết quả là xuất hiện routing loop.

7

HANDBOOK OF ALGORITHMS FOR PHYSICAL DESIGN AUTOMATION PART 100 DOCX

One of the goals in developing GAMA was to perform mapping and placement with little compu- tational effort. To achieve a linear time complexity, the authors limit the search space by considering only a subset of solutions, which means they might not produce an optimal solution. Because optimal mapping of directed acyclic graphs (DAGs) is NP-complete, GAMA first splits the circuit graph into a forest of trees before processing it by the mapping and placement steps. The tree covering algorithm does not directly handle cycles or nodes with multiple fanouts, and might duplicate nodes to reduce the number of trees. Each tree is compared to elements from a preexisting pattern library that contains compound modules such as the one shown in Figure 46.12. Dynamic programming is used to find the best cover in linear time. After the tree covering process, a postprocessing step is attempted to find opportunities for local optimization at the boundaries of the covered trees. Interested readers are referred to Ref. [29] for more details on the mapping process of GAMA.

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THE COMPLETE IS IS ROUTING PROTOCOL P9 PPSX

Figure 3.11 presents an overview of how the commit and rollback commands syn- chronize between the active, candidate and historical conﬁguration ﬁles. When you ﬁrst go into the conﬁguration mode, it means that up to now there has been no candidate conﬁguration, and the candidate conﬁguration is copied unchanged from the active conﬁguration. If a change to the candidate conﬁguration is made and commit- ted, then the candidate conﬁguration replaces the active conﬁguration. The old active conﬁguration is moved into the “archives”. Historical conﬁgurations in the archive are numbered like the log rotation tools you may know from UNIX operating systems. Up to ﬁfty instances of the ﬁle are kept. During a commit operation, historical ﬁle #49 is rolled out and deleted. The remaining other nine conﬁguration ﬁles are renamed. Conﬁg #1 becomes Conﬁg #2, Conﬁg #2 becomes Conﬁg #3. And ﬁnally the previous active con- ﬁguration becomes historical Conﬁg #1.

10

PROGRAMMING A PIVOT TABLE

Figure 11-7. Module-level variable in the General Declarations section ■ Tip The Option Explicit setting ensures that all the variables you use are declared in the code. Using this setting is good practice, as it can help you prevent errors when you write or edit code. You can type Option Explicit at the top of each module, or you can change a setting, so it automatically appears in new modules. In the VBE, click the Tools menu, and then click Options. On the Editor tab, add a check mark to Require Variable Declaration.

41

CREATING A PIVOT TABLE

1.5. Preparing the Source Data: Excel Field Names Not Valid Problem You entered your company’s sales order data on an Excel worksheet, and you want to create a pivot table from that data. On the Ribbon’s Insert tab, you clicked the PivotTable command, and selected a source range in the Create PivotTable dialog box. When you clicked the OK but- ton, a confusing error message appeared: “The PivotTable field name is not valid. To create a PivotTable report, you must use data that is organized as a list with labeled columns. If you are changing the name of a PivotTable field, you must type a new name for the field.” You haven’t named any fields, and you aren’t sure what the message means. This problem is based on the sample file named FieldNames.xlsx.

20

ENVIRONMENTAL STUDIES PART 4 DOCX

Until relatively recently in humanity's history, where pollution has existed, it has been primarily a local problem. The industrialization of society, the introduction of motorized vehicles, and the explosion of the human population, however, have caused an exponential growth in the production of goods and services. Coupled with this growth has been a tremendous increase in waste by- products. The indiscriminate discharge of untreated industrial and domestic wastes into waterways, the spewing of thousands of tons of particulates and airborne gases into the atmosphere, the "throwaway" attitude toward solid wastes, and the use of newly developed chemicals without considering potential consequences have resulted in major environmental disasters, including the formation of smog in the Los Angeles area since the late 1940s and the pollution of large areas of the Mediterranean Sea. Technology has begun to solve some pollution problems, and public awareness of the extent of pollution will eventually force governments to undertake more effective environmental planning and adopt more effective antipollution measures.

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Formatting a Pivot Table

Formatting a Pivot Table N ew formatting features were introduced for pivot tables in Excel 2007, including PivotTable Styles, Document Themes, Conditional Formatting, and Report Layouts, which add many exciting options for enhancing the look of your pivot tables. Questions about these new fea- tures are addressed in this chapter. Common problems with pivot table formatting include loss of formatting when the pivot table is changed or refreshed, showing or hiding subtotals and grand totals, and retaining formats applied in the source data.

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GIÁO TRÌNH CIS PART 38 PPT

Routing protocol: là ngôn ng ữ để một router trao đổi với router khác để chia s ẻ thông tin định tuyến về khả năng đến được cũng như trạng thái của m ạng. Được cài đặt tại các Router, chúng được sử dụng để: xây dựng n ên b ảng định tuyến để đảm bảo rằng tất cả các Router đều có bảng “Routing table ” tương thích nhau cũng như đường đi đến các mạng phải được xác định

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PRACTICAL TCP IP AND ETHERNET NETWORKING P28 PPTX

Routers in different ASs, however, cannot use IGPs for communication for more than one reason. Firstly, IGPs are not optimized for long-distance path determination. Secondly, the owners of ASs (particularly Internet service providers) would find it unacceptable for their routing metrics (which include sensitive information such as error rates and network traffic) to be visible to their competitors. For this reason routers that communicate with each other and are resident in different ASs communicate with each other using exterior gateway protocols.

5

CISCO NETWORK PART 37 PDF

Routing protocol: là ngôn ng ữ để một router trao đổi với router khác để chia s ẻ thông tin định tuyến về khả năng đến được cũng như trạng thái của m ạng. Được cài đặt tại các Router, chúng được sử dụng để: xây dựng n ên b ảng định tuyến để đảm bảo rằng tất cả các Router đều có bảng “Routing table ” tương thích nhau cũng như đường đi đến các mạng phải được xác định

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GIÁO TRÌNH ADVANCED CERTIFICATE IN INFORMATION TECHNOLOGY SANLEIN PART 38 PPSX

Routing protocol: là ngôn ng ữ để một router trao đổi với router khác để chia s ẻ thông tin định tuyến về khả năng đến được cũng như trạng thái của m ạng. Được cài đặt tại các Router, chúng được sử dụng để: xây dựng n ên b ảng định tuyến để đảm bảo rằng tất cả các Router đều có bảng “Routing table ” tương thích nhau cũng như đường đi đến các mạng phải được xác định

9

The Routing Table: A Closer Look pot

First, you must understand a very simple logic. Here is the logic: Me and you are on a journey. If you break my leg, then you must carry me all the way! If you understand this logic, you will understand "IP classless". RIP is telling you: I am classful, if you break my class, then you have to show me every route there is, or I will drop your packet. I will drop it even though there is a default route (0.0.0.0).

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CCNA 1 AND 2 COMPANION GUIDE REVISED CISCO NETWORKING ACADEMY PROGRAM PART 73 PDF

Each router that uses distance vector routing begins by identifying its neighbors. Fig- ure 15-17 shows distance vector discovery. The interface that leads to each directly connected network is shown as having a distance of 0. As the distance vector network discovery process proceeds, routers discover the best path to destination networks based on the information they receive from each neighbor. For example, Router A learns about other networks based on the information that it receives from Router B. Each of the other network entries in the routing table has an accumulated distance vector to show how far away that network is in a given direction.

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PRACTICAL TCP IP AND ETHERNET NETWORKING P14 PPT

One of the earlier EGPs was, in fact called EGP! The current de facto Internet standard for inter-domain (AS) routing is border gateway patrol version 4, or simply BGP-4. (-6 BGP-4, as detailed in RFC 1771, performs intelligent route selection based on the shortest autonomous system path. In other words, whereas interior gateway protocols such as RIP make decisions on the number of ROUTERS to a specific destination, BGP-4 bases its decisions on the number of AUTONOMOUS SYSTEMS to a specific destination. It is a so-called path vector protocol, and runs over TCP (port 179).

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I CƯƠNG VỀ ĐỊNH TUYẾN PPS

Nó sử dụng các bảng “Routing Table” mà Routing Protocol xây dựng lên để đảm bảo việc truyền dữ liệu qua mạng một cách tin cậy. Ví dụ: IP và IPX. I. 3. Vùng tự trị AS (Autonomous System) Mạng Internet được chia thành các vùng nhỏ hơn gọi là các vùng tự trị (Autonomous System – AS ). AS bao gồm một tập hợp các mạng con được kết nối với nhau bởi Router. Một hệ thống AS thông thường thuộc quyền sử hữu của một công ty hay nhà cung cấp dịch vụ Internet (ISP). Và để các hệ thống AS này kết nối được với nhau, nhà quản lý phải đăng ký với cơ quan quản trị mạng trên Internet (Inter NIC) để lấy được một số nhận dạng AS cho riêng mình. Bên trong mỗi AS, các nhà quản lý có quyền quyết định loại Router cũng như giao thức định tuyến cho hệ thống của mình.

7

CCNA 2 CHAPTER 5 POT

Refer to the exhibit. The Ethernet interface on Router2 goes down and the administrator notices that the route is still in the Router1 routing table. How much longer will Router1 keep the down network in its routing table before marking it as possibly down? 30 seconds 90 seconds

6

GIÁO TRÌNH ADVANCED CERTIFICATE IN INFORMATION TECHNOLOGY SANLEIN PART 20 DOC

Với kỹ thuật này trong thực tế tình huống trên sẽ không xảy ra. Bất cứ khi nào một router tạo ra một địa chỉ summary thì router sẽ tạo ra một tuyến tới null interface. Quay trở lại tình huống trên nếu Robinson nhận được một packet với địa chỉ đích thuộc subnet 192.168.3.192/27 và subnet đó không đến được nữa thì router sẽ forward packet đó tới null interface. Routing loop đã được giải quyết.

7

MULTIBOOKS - TỔNG HỢP IT - PC PART 252 DOC

Đối với các router chạy link state routing protocol th ì bình th ường nó chỉ trao đổi b ản tin Hello để duy tr ì neighbor mà không trao đổi các tuyến với nhau. V à nó xây d ựng l ên các tuy ến (route) dựa v ào link state database c ủa nó. Do đó route filter không có ảnh hưởng trong việc quảng bá thông tin trạng thái. Kết quả l à route filter ch ỉ có ảnh hưởng đến routing table của router mà được cấu h ình route filter mà không ảnh hưởng tới các mục nhập tuyến của router neighbor. Chính điều n ày d ẫn

5

THIẾT BỊ MẠNG PPT

– Cho phép n ố i k ế t các ph ầ n m ạ ng c ủ a cùng m ộ t m ạ ng logic s ử d ụ ng ki ể u cáp khác nhau • Bất lợi – Không cho phép k ế t n ố i các ki ể u m ạ ng logic khác nhau – Không cho phép gi ả m t ả i m ạ ng

8

BÀI GIẢNG MẠNG MÁY TÍNH VÀ INTERNET CHƯƠNG 4 TRẦN QUANG HẢI BẰNG

GIAO THỨC TẦNG MẠNG 19 23/08 - 10/10/2010 THE INTERNET TCP/IP NETWORK LAYER routing table _NETWORK LAYER ĐƯỢC THỰC THI TẠI END SYSTEM CŨNG NHƯ TẠI ROUTER!_ Routing protocols •path select[r]

39

THE HANDBOOK OF AD HOC WIRELESS NETWORKS 7 PPT

six o rbital planes. The satellites transmit navigation messages periodically. Each navigation message contains the satellite’s orbit element, clock, and status. After receiving the navigation messages, a GPS receiver can determine its position and roaming velocity. To determine the receiver’s longitude and latitude, we need at least three satellites. If we also want to determine the altitude, another satellite is needed. More satellites can increase the positioning accuracy. The positioning accuracy of GPS ranges in about a few tens of meters. GPS receivers can be used almost anywhere near the surface of the Earth. By connecting to a GPS receiver, a mobile host will be able to know its current physical location. This can greatly help the performance of a MANET, and it is for this reason that many researchers have proposed to adopt GPS in MANETs. For example, mobile hosts in a MANET can avoid using nạve flooding to find routes; neighbors’ or destinations’ locations may be used as a guideline to find routing paths efficiently. Several works have addressed location-aware routing protocols for MANETs [Jain et al., 2001; Karp and Kung, 2000; Ko and Vaidya, 1998; Lin and Stojmenovic, 1999; Mauve and Widmer, 2001; Stojmenovic and Lin, 2001]. Proposals that partition the physical area into nonoverlapping zones to facilitate routing have also been proposed [Joa-Ng and Lu, 1999; Liao et al., 2001]. One interesting feature of such zone-based protocols is that a host can easily decide which zone it belongs to, and only one representative host needs to be active to collect routing-related information. The route search cost can be reduced significantly too since nonrepresentative hosts will not flood the route request packets.

50

THE_HANDBOOK_OF_AD_HOC_WIRELESS_NETWORKS_9 POT

diff erent assumptions and implementation levels. Nevertheless, there are three major issues involved in energy aware routing protocols. First, the goal is to find the path that either minimizes the absolute power consumed or balances the energy consumption of all mobile nodes. Balanced energy consumption does not necessarily lead to minimized energy consumption, but it keeps a certain node from being overloaded and thus ensures longer network lifetime. Since energy balance can be achieved indirectly by distributing network traffic, one such routing protocol is also discussed in this section. Second, energy awareness has been either implemented at purely routing layer or routing layer with help from other layers such as MAC or application layer. For example, information from the MAC layer is beneficial because it usually supports power saving features that the routing protocol can exploit to provide better energy efficiency. Third, some routing protocols assume that the transmission power is controllable and nodes’ location information are available (e.g., via GPS). Under these assumptions, the problem of finding a path with the least consumed power becomes a conventional optimization problem on a graph where the weighted link cost corresponds to the transmission power required for transmitting a packet between the two nodes of the link.

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I CƯƠNG VỀ ĐỊNH TUYẾN (--) POTX

Nó sử dụng các bảng “Routing Table” mà Routing Protocol xây dựng lên để đảm bảo việc truyền dữ liệu qua mạng một cách tin cậy. Ví dụ: IP và IPX. I. 3. Vùng tự trị AS (Autonomous System) Mạng Internet được chia thành các vùng nhỏ hơn gọi là các vùng tự trị (Autonomous System – AS ). AS bao gồm một tập hợp các mạng con được kết nối với nhau bởi Router. Một hệ thống AS thông thường thuộc quyền sử hữu của một công ty hay nhà cung cấp dịch vụ Internet (ISP). Và để các hệ thống AS này kết nối được với nhau, nhà quản lý phải đăng ký với cơ quan quản trị mạng trên Internet (Inter NIC) để lấy được một số nhận dạng AS cho riêng mình. Bên trong mỗi AS, các nhà quản lý có quyền quyết định loại Router cũng như giao thức định tuyến cho hệ thống của mình.

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MODULE 3 MULTIAREA OSPF OPERATION PPTX

CCNP – BSCI Bachkhoa Networking Academy LSA Types: 6, 7, 8  Group Membership LSAs are used in an enhancement of OSPF known as Multicast OSPF (MOSPF). MOSPF routes packets from a single source to multiple destinations, or group members, which share a class D multicast address. Although Cisco supports other multicast routing protocols, MOSPF is not supported as of this writing.

34

CISCO NETWORK PART 19 POT

1. Phân phối lại với tóm lược tuyến (Redistribution và RouteSummarization) a. Tóm lược tuyến (Route Summarization) Trong một routing domain, khi một topo mạng càng lớn thì kích thước routing table của các router trong domain đó không những có kích thước càng lớn mà còn rất khó khăn cho các nhà quản trị gỡ dối mạng cũng như yêu cầu rất cao về phần cứng của router. Có một giải pháp giải quyết vấn đề này đó là route summarization. Bằng cách nhóm các subet con thành một subnet đại to hơn.

7