membership.embedded-vision.com/the-darker-side-of-paradise.php The source sends traffic to the Class D address, and through switch and router protocols, packets are forwarded only to intended stations. As you do your multicast design, also be aware of the potential for duplicate packets being received and the potential for packets arriving out of order. In addition to Layer 3 addresses, multicast applications must have Layer 2 addresses that is, MAC addresses.
Fortunately, these Layer 2 addresses can be constructed directly from the Layer 3 multicast addresses. The 25 bit is always 0. The last 23 bits in the multicast MAC address come directly from the last 23 bits of the multicast IP address. Consider the following example: n Given a multicast IP address of If the leftmost bit isnt already 0, it should be changed to 0, because the 25 bit of a multicast MAC address is. Convert each nibble that is, 4-bit section into its hexadecimal equivalent. Prepend e to the calculated address to produce the multicast MAC address.
This overlap issue permits 32 Layer 3 multicast addresses to map to the same Layer 2 multicast MAC address. Therefore, care must be taken when selecting Layer 3 multicast addresses to avoid this overlap. As previously mentioned, in a multicast network, the source sends multicast packets with a Class D destination address. The Some ranges of addresses in the Class D address space are dedicated for special purposes: Protocol uses Other well-known addresses in this range include Version 3 IGMPv3 , to allow a multicast receiver request, not only membership in a group, but also to request specific sources to receive traffic from.
Therefore, in an SSM environment, multiple sources with different content can all be sending to the same multicast destination address. As an. The autonomous system number is used to calculate. First, convert the autonomous system number to hexadecimal that is, in decimal equals FD-E8 in hexadecimal.
FD in hexadecimal equals in decimal, and E8 in hexadecimal equals in decimal. The first octet of a GLOP address is always The protocol used between clients for example, PCs and routers let routers know which of their interfaces have multicast receivers attached is IGMP. There can be up to a threeminute delay before a router realizes that a receiver left the group. The destination address of this router query is Specifically, a receiver can proactively send a leave message when it no longer wants to participate in a multicast group, allowing the router to prune its interface earlier.
Only members of a multicast group receive packets destined for that group. However, the sender does not need to be a member of the group. Multicast traffic flows from a source to a destination over a distribution tree, which is a loop-free path. The two types of distribution trees are as follows: n Source distribution tree: A source distribution tree creates an optimal path between each source router and each. To combat the issue of receiving duplicate packets, Cisco routers perform an RPF reverse path forwarding check, to determine whether a multicast packet is entering a router on the correct interface.
An RPF check examines the source address of an incoming packet and checks it against the routers unicast routing table to see what interface should be used to get back to the source network. If the incoming multicast packet is using that interface, the RPF check passes, and the packet is forwarded. If the multicast packet is coming in on a different interface, the RPF check fails, and the packet is discarded, as illustrated in Figure When a Layer 2 switch receives a multicast frame on an interface, by default, the switch floods the frame out all other interfaces.
To prevent this behavior, the switch needs awareness of what interfaces are connected to receivers for specific multicast groups. One approach to training the switch is IGMP snooping. IGMP Snooping allows a switch to autonomously determine which interfaces are connected to receivers for specific multicast groups by eavesdropping on the IGMP traffic being exchanged between clients and routers. Specifically, ASM allows routers to explicitly request to join a tree using a shared distribution tree approach, and then performs SPT switchover, allowing receiver routers to form a shortest path tree with the source routers, thus creating optimal pathing.
This approach eliminates the need for an RP. Whereas unicast routing maintains a unicast routing table, IP multicast routing relies on multicast state information, which is maintained in the multicast routing table, in addition to the unicast routing table. Unicast routing can use technologies such as access control lists ACL or firewalls to protect traffic.
These technologies can prevent one device from sending traffic to another device. However, with IP multicast routing, traffic is sent to a multicast group rather than a specific device. Therefore, a major IP multicast security consideration is to protect multicast receivers from unknown senders. Fortunately, SSM prevents an unknown host from sending to a multicast receiver, because with SSM a multicast receiver joins to a specific host. Also, with Any-Source Multicast, a receiver would only be susceptible to a multicast attack if it joined a multicast group.
To limit IP multicast traffic from being propagated too far within a network, scopes can be used to set boundaries for the traffic. In addition, consider the following approaches for securing IP multicast networks: n Packet filter based access control: Typically used for inbound traffic, packet filter based access control can filter. Interestingly, these diverse technologies can be used in tandem to provide VoIP services for wireless clients. Introduction to VoWLAN Technologies A WLAN contains access points with which wireless devices communicate , antennas which help determine the wireless coverage areas , and wireless endpoints such as a laptop containing a wireless network interface card.
Cisco offers a suite of wireless technologies that fall under the umbrella of the Cisco Unified Wireless Network. An example of a wireless network, demonstrating various wireless bridging methods, is illustrated in Figure Elements of a Cisco Unified Wireless Network include mobility services, network management services, network unification, access points, and client devices. Although some might argue that cell phones provide an alternative solution to mobile communications, VoWLAN services offer access to a wider range of enterprise voice applications for example, access to a corporate phone directory.
Specifically, if VoIP packets experience excessive packet drops, jitter that is, a variation in interpacket arrival times , and delay, the voice quality will be considered unacceptable by the end users. The G. Specifically, the G. Fortunately, Cisco offers an array of quality of service QoS solutions that can help minimize packet loss, jitter, and overall delay for voice traffic. Cisco uses the terminology of Cisco voice-ready architecture to describe their end-to-end solution for WLANs that can transmit VoIP traffic, while maintaining voice quality.
Fortunately, Cisco Unified Wireless Network offers a variety of products for ensuring appropriate coverage. To maintain a more consistent call quality, Cisco recommends the following radio frequency RF parameters: n Wireless signal stream of 67 dBm or greater n A maximum packet error rate of 1 percent n A minimum signal-to-noise ratio SNR of 25 dB.
A wireless access point shares bandwidth among its clients. Additional bandwidth per client can be achieved by adding access points. However, to prevent RF interference, adjacent wireless access points should use different frequencies that is, channels.
These channels should be nonoverlapping channels. Nonoverlapping channels extend coverage while maintaining available bandwidth.
The three nonoverlapping channels commonly used in North America are channels 1, 6, and To provide continuous coverage, as wireless devices roam from one cell to another cell, Cisco recommends a 15 percent to 20 percent cell coverage overlap. Although multiple IEEE Specifically, Performing an effective site survey involves the following steps: 1. Determine what type of devices the customer needs to support, the number of devices, the service levels of those. Review potential structural elements walls, stairwells, or elevator shafts that will impede the propagation of the.
Identify initial access point locations. With the access points in place, conduct the site survey which identifies the coverage areas and signal strengths that. Cisco wireless devices support various types of roaming, as illustrated in Figure Cisco recommends that voice traffic and data traffic be placed in separate VLANs.
This VLAN separation enables the use of various security features and also aids in the prioritization of voice traffic. Whereas the The G is flexi-. We discuss the implementation of the Cisco IOS Software management instrumentation functionality as part of overall enterprise design. Built-In Management Capabilities Large enterprises rely on WAN links, but there are several issues with these, including the following: n High cost, leading to implementation of low-speed lower-cost links n Speed mismatches between LAN and WAN links leading to congestion, packet loss, and so on n Combination of real-time applications competing for bandwidth with general data transfer.
Cisco application optimization cycle: 1. Create baseline of application traffic. Meet objectives through optimization. Cisco IOS System Message Logging syslog : Syslog allows reporting and archiving of error messages locally or on a remote logging server. NetFlow usage: Used both by service providers and enterprise organizations, although their usage of it may differ. For service providers SP , it can provide assistance with traffic engineering, network planning, accounting and billing, security monitoring, and information regarding peering arrangements. Enterprises typically use NetFlow for user and Internet access monitoring, application monitoring, charge-back billing for departments, and security monitoring.
Defining a flow: A flow in NetFlow consists of seven fields: IP source address, IP destination address, source port number destination port number, Layer 3 protocol type, type-of-service ToS byte, and input logical interface. NetFlow inspects packets for key field values and compares these to existing flows in the cache. If the values are unique, a flow is created in the cache. By examining flows and caching information about unique values, NetFlow-enabled switching can provide scalability and performance based on flow cache management.
NetFlow Version 9: This version has an export format that allows new fields to be easily inserted. It includes a template that describes what is being exported in the export data sets. A matching ID number is then used to associate templates to the data records. Flexibility: Network managers have the flexibility to configure what key and nonkey fields define each flow. This helps provide enhanced optimization of network infrastructure while reducing costs and improving capacity planning and security detection.
As an example, if a company had an autonomous system number of , its globally unique range of multicast IP addresses would be You can also run through a lab de-brief, view configurations, and cut and paste configs into your own lab equipment for testing and verification. EtherChannel utilization can be further optimized with the Min-Link feature, which allows for the specification of a minimum number of available ports for a PortChannel to be considered a valid path. Cisco uses the terminology of Cisco voice-ready architecture to describe their end-to-end solution for WLANs that can transmit VoIP traffic, while maintaining voice quality. This digital Short Cut provides you with detailed, graphical-based information, highlighting only the key topics in cram-style format. Specifically,
Deployments vary with smaller deployments using a single server for both reporting and collecting, whereas with large-scale deployments, a two-tier architecture that uses collectors at key sites is often used. By adding classification to the network, it can deliver more granular identification and control over multiple applications, which common quality of service QoS mechanisms cannot differentiate.
Characteristics of NBAR: n Provides full-packet inspection to identify traffic types n Discovers application protocol statistics on interfaces n Enables application of QoS policies to traffic flows.
Per-protocol statistics: NBAR Discovery Protocol discovers any protocol traffic supported by NBAR and maintains perprotocol statistics for enabled interfaces with regard to the following: n Total number of input packets and bytes n Total number of output packets and bytes n Input bit rates n Output bit rates.
AutoQoS for VOIP creates predefined maps for voice traffic; whereas AutoQoS Enterprise uses NBAR discovery mode to pull together traffic statistics, and then creates a policy map based on the traffic that was detected, with suggested bandwidth settings per class. Overview of IP SLA A service level agreement SLA is used by organizations to specify connectivity and performance levels for an end-user service from a provider of that service.
The SLA is a contract between the network provider and its customers, or internally between the department responsible for the network and internal corporate customers. Benefits of service level agreements include the following: n Guarantee regarding service level n Connectivity and performance are specified with regard to end-user service n Helps support isolation of problems and network planning.
Embedded Cisco IOS IP SLA measurements, on Cisco network equipment, can verify service agreements, validate network performance, improve network reliability, and proactively identify network issues, and can also react to performance metrics with changes both to configuration and network.
These operations are divided into two classes. Active measurement: In contrast to NetFlow, which passively monitors the network, the Cisco IOS IP SLA measurements actively send data across the network to measure performance between multiple network locations on a hop-by-hop basis or across end-to-end network paths. Having a dedicated router or shadow router has a number of advantages: n Separate memory and CPU from hardware in switching path n Easy upgrade of Cisco IOS Software release on the dedicated router n Flexibility of management and deployment n Scalability with a large number of endpoints.
If you are working with a large number of sites, a hierarchical strategy might be needed for IP SLA enterprise monitoring. When selecting a network management application, you must consider three main things: n How the application supports provisioning IP SLA operations n How the network management application supports reporting on IP SLA operations n Whether the tool supports aggregation of hierarchical measurements for a more scalable set of measurements. Read Free For 30 Days.
Flag for inappropriate content. Related titles. Carousel Previous Carousel Next. Jump to Page. Search inside document. To identify customer requirements, obtain the following pieces of information: n Network applications n Network services n Business goals n Constraints imposed by the customer n Technical goals n Constraints imposed by technical limitations 2. Identify characteristics of the current network. To identify characteristics of the current network, perform the following tasks: n Collect existing network documentation with the understanding that the documentation might be somewhat dated and unreliable , and interview organizational representatives to uncover information not available in the documentation.
Design the network topology. Transport Network Data Link Physical Using a top-down design strategy, as opposed to a bottom-up design strategy that is, where the design begins at the physical layer of the OSI model and works its way up provides the following benefits: n Does a better job of including specific customer requirements n Offers a more clearly articulated big picture of the desired network for both the customer and the designer n Lays the foundation for a network that not only meets existing design requirements, but also provides scalability to meet future network enhancements Cisco Systems Inc.
Those three layers, as shown in Figure , are as follows: n Access layer: Typically, wiring closet switches connecting to end-user stations n Distribution layer: An aggregation point for wiring closet switches, where routing and packet manipulation occur, and also where the campus network interconnects to remote networks n Core layer: The network backbone where high-speed traffic transport is the main priority Cisco Systems Inc. Cisco developed its own method of providing Power Cisco Systems Inc.
Designing IP Addressing Good IP addressing design uses summarizable blocks of addresses that enable route summarization and provides a number of benefits: n Reduced router workload and routing traffic n Increased network stability n Faster convergence n Significantly simplified troubleshooting Creating and using summary routes depends on the use of summarizable blocks of addresses. Hub Should be an ABR so that each area may be summarized into the other areas.
Use fast hellos only if the number of neighbors is reasonably small. There are two alternatives to address this, route reflectors and confederations: n Route reflectors: A route reflector is an iBGP speaker that reflects routes learned from iBGP peers to other iBGP peers. Core and Aggregation Layer Infrastructure Design The three layer data center design is as follows: n Core layer: Composed of the high-speed packet-switching backplane n Aggregation layer: Provides service module integration, Layer 2 domain definitions, spanning-tree processing, and default gateway redundancy n Access layer: Provides physical connection for servers to the network Data center core layer design: Core layer allows for high-speed packet switching between multiple aggregation modules.
Enhanced Interior Gateway Routing Protocol EIGRP routing recommendations include the following: n Use the ip summary-address eigrp command to advertise a default summary route into the data center and to summarize the data center subnets. Aggregation layer design: A pair of interconnected aggregation switches, referred to as modules, are used to scale the aggregation layer through the following: n Spanning-tree scaling n Access layer density scaling n Hot Standby Router Protocol HSRP scaling n Application services scaling If Layer 2 is used, special consideration should be given to Spanning Tree Protocol STP design because the aggregation modules allow the spanning-tree domain to be distributed.
Blade server challenges and considerations: n Administrative domains n Interoperability n Spanning-tree scaling n Pass-through cabling n Switch trunk topologies n Environmental Issues Blade server connectivity: Blade servers can support either Layer 2 or Layer 3 topologies depending on the server broadcast domain or specific administrative requirements. Collapsed core design: n Single-switch design: Provides percent port design efficiency with a generally lower subscription ratio, while allowing empty slots to support future growth.
The OER cycle is learn, measure, apply policy, optimize, and verify. Cisco firewalls use one of two basic modes of operation: n Routed mode: The traditional mode of operation, where the firewall acts as a Layer 3 device n Transparent mode: A newer mode of operation, where the firewall acts as a Layer 2 device, with each interface residing on the same subnet but on different VLANs Cisco IOS Software has a firewall feature set available, through which a router can act as a firewall.
Examples of these dedicated appliances include the following: n PIX: Ciscos traditional firewall, which allows traffic from a higher-security interface for example, the inside network to a lower-security interface for example, the outside network n ASA: Cisco Adaptive Security Appliance, which offers other services for example, virtual private network [VPN] and intrusion prevention in addition to firewall services n FWSM: Cisco Firewall Services Module for the Catalyst series switch, which unlike the PIX and ASA, does not permit any traffic flow between interfaces unless configured to do so with the exception of Address Resolution Protocol ARP traffic Modern Cisco firewalls can contain contexts, which act as virtual firewalls within a single physical firewall.
Virtual firewalls can often benefit service providers, who can have a single physical device Cisco Systems Inc. Among the supported NAC Appliance designs are the following: n Layer 2 in-band: The most popular type of NAC Appliance deployment, where the NAS is logically, but not physi- cally, inline with the client data, as depicted in Figure n Layer 2 out-of-band: Similar to the Layer 2 in-band design, with the exception of a trunk carrying traffic from the posture assessment and the network access VLANs being used between the access and distribution switches Cisco Systems Inc.
These sensors can be a dedicated network appliance or software than runs on a host for example, Cisco Security Agent. Two protocols that make this secure transmission possible are as follows: n IPsec: IPsec is normally used to secure the transmission of data. These address pools are pointed to by the static routes mentioned in the preceding bullet. However, other authentica- tion solutions can be used along with SSL.
When interconnecting multiple sites using VPN technologies, consider the following deployment models: n Peer-to-peer: Secures traffic between two sites n Hub and spoke: A common approach, in which remote sites connect back to a central location n Partial mesh: Builds on a hub-and-spoke topology to provide direct connections between some remotes, to better accommodate for traffic patterns n Full mesh: Provides direct connections between each location in the VPN topology The three primary approaches for placing a VPN device in an enterprise campus design are as follows: n Placing the VPN device parallel to the firewall, which supports high scalability n Placing the VPN in a firewalls DMZ, which supports the inspection of decrypted IPsec traffic n Integrating the VPN device with the firewall, resulting in fewer devices to manage Cisco Systems Inc.
The Easy VPN server can push security policies to remote sites. First, convert the last three octets to binary. If the leftmost bit isnt already 0, it should be changed to 0, because the 25 bit of a multicast MAC address is always 0. As an example, if a company had an autonomous system number of , its globally unique range of multicast IP addresses would be The autonomous system number is used to calculate Cisco Systems Inc.
The two types of distribution trees are as follows: n Source distribution tree: A source distribution tree creates an optimal path between each source router and each last-hop router that is, a router connected to a receiver , at the expense of increased memory usage, as shown in Figure In addition, consider the following approaches for securing IP multicast networks: n Packet filter based access control: Typically used for inbound traffic, packet filter based access control can filter traffic before IP multicast routing occurs.
To maintain a more consistent call quality, Cisco recommends the following radio frequency RF parameters: n Wireless signal stream of 67 dBm or greater n A maximum packet error rate of 1 percent n A minimum signal-to-noise ratio SNR of 25 dB A wireless access point shares bandwidth among its clients. Determine what type of devices the customer needs to support, the number of devices, the service levels of those devices, and the location of the devices to be supported. Download Free dumps to do positive that you understand braindumps well.
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AREI abbreviation. De twee belangrijkste problemen in verband met het AREI, waarmee een , , en […]. September 25, by admin No comments. September 24, by admin No comments. September 23, by admin No comments. September 22, by admin No comments. September 21, by admin No comments.