Friday, September 21, 2018

Networking Basics: Routers

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Networking Basics: Routers

When looking at networking basics, understanding the way a network operates is the first step to understanding routing and switching. The network operates by connecting computers and peripherals using two pieces of equipment; switches and routers. 

Switches and routers, essential networking basics, enable the devices that are connected to your network to communicate with each other, as well as with other networks.Though they look quite similar, routers and switches perform very different functions in a network.

Routers, the second esteemed component of our networking basics and are used to tie multiple networks together. For example, if we would use a router to connect your networked computers to the Internet and thereby share an Internet connection among many users. The router will act as a correspondent, choosing the best route for your communication to travel so that you receive it quickly.

Routers analyze the data being sent over a network, change how it is packaged, and send it to another network, or over a different type of network. They connect your business to the outside world, protect your information from security threats, and can even decide which computers get priority over others

Fig 1.1- Basics of Router
Depending on your business and your networking plans, you can choose from routers that include different capabilities. These can include networking basics such as:
  • Firewall: Specialised software that examines incoming data and protects your business network against attacks
  • Virtual Private Network (VPN): A way to allow remote employees to safely access your network remotely
  • IP Phone network : Combine your company's computer and telephone network, using voice and conferencing technology, to simplify and unify your communications

There are lot of Cisco Router Models used in small, Big, Enterprise and Datacenter environment, Some of them are the below models used by the Cisco:-

Tuesday, September 11, 2018

Comparing : Li-Fi and Wifi Technology

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#Advance Technology 
#Li-FI Technology
What is “LiFi”?

Prof. Harald Haas coined the term “LiFi” at his TED Global talk to describe the high speed, bidirectional, networked and mobile wireless communication of data using light.

Li-Fi is a bidirectional, high speed and fully networked wireless communication technology similar to Wi-Fi. Coined by Prof. Harald Haas, Li-Fi is a subset of optical wireless communications (OWC) and can be a complement to RF communication (Wi-Fi or Cellular network), or a replacement in contexts of data broadcasting.

It is wireless and uses visible light communication or infra-red and near ultraviolet (instead of radio frequency waves) spectrum, part of optical wireless communications technology, which carries much more information, and has been proposed as a solution to the RF-bandwidth limitations. A complete solution includes an industry led standardization process.

Watch the below Video for more Information:
Li-fi can deliver internet access 100 times faster than traditional wi-fi, offering speeds of up to 1Gbps (gigabit per second).
It requires a light source, such as a standard LED bulb, an internet connection and a photo detector.
It was tested this week by Estonian start-up Velmenni, in Tallinn.

Velmenni used a li-fi-enabled light bulb to transmit data at speeds of 1Gbps. Laboratory tests have shown theoretical speeds of up to 224Gbps.

It was tested in an office, to allow workers to access the internet and in an industrial space, where it provided a smart lighting solution.

Fig 1.1- Lifi Vs Wifi

The term li-fi was first coined by Prof Harald Haas from Edinburgh University, who demonstrated the technology at a Ted (Technology, Entertainment and Design) conference in 2011.

Prof Haas described a future when billions of light bulbs could become wireless hotspots.
One of the big advantages of li-fi is the fact that, unlike wi-fi, it does not interfere with other radio signals, so could be utilised on aircraft and in other places where interference is an issue.
While the spectrum for radio waves is in short supply, the visible light spectrum is 10,000 times larger, meaning it is unlikely to run out any time soon.

But the technology also has its drawbacks - most notably the fact that it cannot be deployed outdoors in direct sunlight, because that would interfere with its signal.

Neither can the technology travel through walls so initial use is likely to be limited to places where it can be used to supplement wi-fi networks, such as in congested urban areas or places where wi-fi is not safe, such as hospitals.

Inter-VXLAN Routing Design

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As with traditional VLAN environment, routing between VXLAN segments or from VXLAN to VLAN segments is required in many situations. Because the current Cisco NX-OS releases (Release 6.1(2)I2(3) and earlier) don’t support VXLAN routing, specific designs need to be applied to achieve this network function.
Inter-VXLAN Routing Design Option A: Routing Block Design
Figure 14 depicts a VXLAN routing solution by adding a routing block to the Layer 3 pod network. The routing block has a router-on-a-stick design consisting of a VTEP or a pair of vPC VTEPs to terminate VXLAN tunnels, and one or a pair of routers that serve as the IP gateway for the VXLAN-extended VLANs and perform routing functions for these VLANs

For Layer 2 traffic within a VXLAN VNI, the traffic will go directly between the local VTEP and the remote VTEPs. For Layer 3 routed traffic between VXLAN VNIs, the traffic will first reach the IP gateway of the source VXLAN VLAN IP subnet that is on the routers in the routing block and will be routed to the destination VXLAN VLAN IP subnet by the gateway router. The gateway router will then forward the packets back to the VTEP in the routing block for encapsulation in the destination VXLAN and forwarding toward the destination host. The logical traffic flow is shown in Figure below:-

Routing Block Configuration
The routing block in the recommended design for VXLAN routing consists of a physical VTEP or vPC VTEP pair that converts VXLAN VNIs back to VLANs, and a router or a pair of routers that functions as the IP gateway for the VLAN IP subnets and routes between VLAN IP subnets. For device redundancy, redundant VTEP devices, such as a pair of Cisco Nexus 9300 as vPC VTEPs and a pair of routers running a first-hop redundancy protocol such as Hot Standby Router Protocol (HSRP), are recommended.

Figure 16 shows a sample VXLAN routing block that is designed with two pairs of Cisco Nexus 9300 platform switches. One pair of Cisco Nexus 9300 platform switches functions as a vPC VTEP that maps between the VXLAN and VLAN. 

The second pair is an IP gateway for the VXLAN-extended VLANs. There is a double-sized vPC between the two pairs of switches for Layer 2 connectivity. A separate set of Layer 3 links can be installed for routing between the VXLAN VLAN to non-VXLAN VLANs or an IP network. The relevant configuration of the devices in the routing block is provided

Note: Because of a known software issue, the peer links of the vPC VTEPs and the Layer 2 links to the routers in the routing block can’t be on the 40 Gigabit Ethernet links of Cisco Nexus 9300 platform switches before Cisco NX-OS Release 6.1(2)I2(2a). This problem is fixed in Cisco NX-OS Release 6.1(2)I2(2a).

Inter-VXLAN Routing Design Option B: VTEP-on-a-Stick Design
One alternative design for inter-VXLAN routing is shown in Figure 17. It has a VTEP-on-a-stick design, in which one or a pair of Cisco Nexus 9300 VTEPs is connected to the aggregation switches through a Layer 2 link and a Layer 3 link. 

The Layer 3 links are used to establish VXLAN tunnels with the in-rack VTEP access switches to extend the host VLANs across the Layer 3 network. The aggregation switches are configured with the host VLANs and switch virtual interfaces (SVIs) for their IP subnets. 

HSRP and Virtual Router Redundancy Protocol (VRRP) can be used to provide the first-hop redundancy with a Layer 2 link in place between the two aggregation switches. The Cisco Nexus 9300 VTEPs map the VXLAN VNIs back to VLANs and send the traffic over the Layer 2 links to the aggregation switches for inter-VLAN routing. 

After the packets are routed to the destination VLAN IP subnet, the aggregation switches will send the packets back to the Cisco Nexus 9300 VTEPs through the Layer 2 links for VXLAN encapsulation. The encapsulated packets will be forwarded to the destination rack through the underlay Layer 3 network. 

In this design, the added Cisco Nexus 9300 VTEPs extend the host VLAN segments and bring them onto the aggregation switches. The aggregation switches are the centralized IP gateway for the VXLAN-extended VLANs.

The VTEP-on-a-stick design keeps the IP gateway of the VXLAN-extended VLANs on the aggregation switches, which preserves the IP gateway placement of the traditional Layer 2 data center pod. However, it may create blocks for migrating the network to a spine-and-leaf fabric architecture in the future. 

The routing block design, by contrast, makes it easier to transform the existing aggregation- and access-layer architecture into a true spine-and-leaf fabric, as shown in Figure below. This architecture truly enables Layer 2 adjacency across a routed (Layer 3) fabric

Currently Cisco Nexus 9300 platform switches support only VXLAN gateway and bridging functions. A planned future release of Cisco NX-OS will bring the VXLAN routing function to the Cisco Nexus 9300 platform, which will greatly simplify the network design for inter-VXLAN routing.
In addition, Cisco is working on a BGP EVPN control plane for VXLAN. The current multicast-based VXLAN lacks a control plane and has to rely on flooding and learning to build the Layer 2 forwarding information base in the overlay network. 

Multicast in the underlay network is used to support the overlay flood-and-learn behavior. The Cisco BGP EVPN control plane is standards based and does not depend on any fabric controllers. It will offer the following main benefits:
 Eliminate or reduce flooding in the data center
 Achieve optimal handling of multiple-destination traffic (broadcast, unknown unicast, and multicast) on overlay networks
 Provide reliable and quick address resolution and updates for hosts in VXLAN VNIs: essential to support workload mobility in the data center
 Provide a distributed anycast IP gateway for VXLAN overlay networks, enabling optimal VXLAN traffic routing across the Layer 3 network
VXLAN is a network virtualization technology. It uses MAC-in-UDP tunneling to build Layer 2 overlay networks across a Layer 3 infrastructure. This approach decouples the tenant network view from the shared common infrastructure, allowing organizations to build a scalable and reliable Layer 3 data center network while maintaining direct Layer 2 adjacency in the overlay network.

Cisco Nexus 9300 platform switches can be physical VTEPs, providing hardware-based high performance. 

VXLAN functions on Cisco Nexus 9300 platform switches are quickly evolving, with inter-VXLAN routing and EVPN control plane functions already planned. After these enhancements become available, the VXLAN overlay design with Cisco Nexus 9300 platform switches can be further optimized and simplified. 

This solution will provide the data center network design for a Layer 2 overlay across a Layer 3 fabric to help provide the application workload mobility and network virtualization required by multitenant environments.

Sunday, September 9, 2018

Cisco ASR 1002-X Basics

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Cisco ASR 1002-X

# Cisco Routers
#CCIE Candidates 
# ASR Routers Specifications
# Capacity and Utilization
# RP and ESP Processors
# RP - Route Processors
# ESP - Embedded Processors

Lets talk about the basics of Cisco ASR 1002-X Router now, Similar with the ASR 1001-X Router but the difference is the inbuilt capacity in the ASR 1002-X Routers differ from ASR 1001-X Routers.

Further we can also discuss the difference between the route processors and Embedded processors and the use of these processors in ASR Routers.

ASR routers are generally used where we have the demand of the high bandwidth, likewise we have the customer and the capacity requirement for the WAN network is more and equal to 1 Gbps and in future the capacity increase to 2,5 or 10 Gbps, then can use ASR routers.

Some of the requirement where we are providing solution in the DC and we need to provide the High end routers as CE routers, then we can have the ASR Routers.

Fig 1.1- ASR 1002-X 

Note: - We can upgrade the back-plane capacity of the ASR routers by putting the license of Embedded processor like ESP-5, ESP-10, ESP-20. So we can upgrade the Back-plane capacity up-to 20 Gbps in ASR Routers.

Further if you guys have any queries about the Cisco ASR Routers in terms of Hardware or the functionality of the routers, we feel free to contact us so that we can explain the information related to the Cisco ASR routers. 

Lets talk about the routers in details as follows:- 

Cisco ASR 1000 series Aggregation services Routers mixture more than one WAN connections and community offerings, which include encryption and traffic management, and forward them across WAN connections at line speeds from 2.5 to 2 hundred Gbps. The routers include each hardware and software program redundancy in an enterprise-leading excessive-availability design.

The today's addition to the Cisco ASR circle of relatives is the Cisco ASR 1001-X Router, a single-rack-unit (RU) router helping 2.5- to twenty-Gbps forwarding ability. Cisco ASR 1001-X Router speeds may be “became up” incrementally to as an awful lot as 20 Gbps with a simple throughput improve license, rather than having to buy additional hardware blades or new routers.

The Cisco ASR a thousand series helps Cisco IOS XE software program, a modular operating system with modular packaging, feature speed, and effective resiliency. The Cisco ASR one thousand collection Embedded offerings Processors (ESPs), that are based on Cisco Quantum float Processor technology, boost up many superior features which includes crypto-based totally access protection; community deal with Translation (NAT), thread protection with Cisco area-primarily based Firewall (ZBFW), deep packet inspection (DPI), Cisco Unified Border element (dice), and a numerous set of information middle interconnect (DCI) capabilities. those offerings are implemented in Cisco IOS XE software program without the want for extra hardware help.

Cisco ASR 1000 Routers sit at the edge of your enterprise data center or large office connecting to the WAN, as well as in service provider points of presence (POPs). The Cisco ASR 1000 Series will benefit the following types of customers:
Enterprises experiencing explosive network traffic as mobility, cloud networking, and video and collaboration usage ramp up. Cisco ASRs consolidate these various traffic streams and apply traffic management and redundancy properties to them to maintain consistent performance among enterprise sites and cloud locations.
Network service providers needing to deliver high-performance services, such as DCI and branch-office server aggregation, to business customers. Service providers can also use the multiservice routers to deploy hosted and managed services to business and multimedia services to residential customers.

Existing Cisco 7200 Series Router (End-of-Sale) customers looking for simple migration to a new multiservice platform that delivers greater performance with the same design.

Cisco Catalyst 3850 Fiber Switch Model

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Cisco Catalyst 3850 is generally new Launched Cisco Switch with the Fiber Connectivity Capabilities. It can be used in the Data-Center environment for various purposes.

Lets discuss about this switch in details as below:

The Cisco Catalyst 3850 Series is the next generation of enterprise-class stackable Ethernet and Multi-gigabit Ethernet access and aggregation layer switches that provide full convergence between wired and wireless on a single platform. Cisco’s new Unified Access Data Plane (UADP) application-specific integrated circuit (ASIC) powers the switch and enables uniform wired-wireless policy enforcement, application visibility, flexibility and application optimization. 

This convergence is built on the resilience of the new and improved Cisco StackWise-480 technology. The Cisco Catalyst 3850 Series Switches support full IEEE 802.3 at Power over Ethernet Plus (PoE+), Cisco Universal Power over Ethernet (Cisco UPOE), modular and field-replaceable network modules, RJ45 and fiber-based downlink interfaces, and redundant fans and power supplies. With speeds that reach 10Gbps, the Cisco Catalyst 3850 Multi-gigabit Ethernet Switches support current and next-generation wireless speeds and standards (including 802.11ac Wave 2) on existing cabling infrastructure

Product Overview
Integrated wireless controller capability with: 
  • Up to 40G of wireless capacity per switch (48-port models) 
  • Support for up to 50 access points and 2000 wireless clients on each switching entity (switch or stack)
  • 24 and 48 10/100/1000 data PoE+ and Cisco UPOE models with energy-efficient Ethernet (EEE) Cisco StackWise-480 technology provides scalability and resiliency with 480 Gbps of stack throughput 
  • Cisco StackPower technology provides power stacking among stack members for power redundancy Three optional uplink modules with 4 x Gigabit Ethernet, 2 x 10 Gigabit Ethernet, or 4 x 10 Gigabit Ethernet ports 
  • Dual redundant, modular power supplies and three modular fans providing redundancy Full IEEE 802.3at (PoE+) with 30W power on all ports in 1 rack unit (RU) form factor 
  • Cisco UPOE with 60W power per port in 1 rack unit (RU) form factor
  • Software support for IPv4 and IPv6 routing, multicast routing, modular quality of service (QoS), Flexible NetFlow (FNF) Version 9, and enhanced security features
  • Single universal Cisco IOS Software image across all license levels, providing an easy upgrade path for software features
  • Enhanced limited lifetime warranty (E-LLW) with next business day (NBD) advance hardware replacement and 90-day access to Cisco Technical Assistance Center (TAC) support

Network Modules
The Cisco Catalyst 3850 Series Switches support three optional network modules for uplink ports. The default switch configuration doesn’t include the uplink module. At the time of switch purchase the customer has the flexibility to choose from the network modules
  • 4 x Gigabit Ethernet with Small Form-Factor Pluggable (SFP)
  • 2 x 10 Gigabit Ethernet with SFP+ or 4 x Gigabit Ethernet with SFP
  • 4 x 10 Gigabit Ethernet with SFP+ (supported on the 48-port models only)
Fig 1.1- Cisco 3850 Switch

The C3850-NM-4-10G module is supported on the 48-port models only. The SFP+ interface supports both 10 Gigabit Ethernet and Gigabit Ethernet ports, allowing customers to use their investment in Gigabit Ethernet SFP and upgrade to 10 Gigabit Ethernet when business demands change without having to do a comprehensive upgrade of the access switch. The three network modules are hot swappable

Power over Ethernet Plus (PoE+)
In addition to PoE (IEEE 802.3af), the Cisco Catalyst 3850 Series Switches support PoE+ (IEEE 802.3at standard), which provides up to 30W of power per port. The Cisco Catalyst 3850 Series Switches can provide a lower total cost of ownership (TCO) for deployments that incorporate Cisco IP phones, Cisco Aironet wireless LAN (WLAN) access points, or any IEEE 802.3at-compliant end device. 

PoE removes the need for wall power to each PoE enabled device and eliminates the cost for additional electrical cabling and circuits that would otherwise be necessary in IP phone and WLAN deployments. Table 6 shows the power supply combinations required for different PoE needs.

Cisco Universal Power over Ethernet (UPOE)
Cisco Universal Power over Ethernet is a breakthrough technology, offering the following services and benefits:
  • 60W per port to enable a variety of end devices such as Samsung VDI client, BT IP turret systems in trading floors, Cisco Catalyst compact switches in retail/hospitality environments, personal Cisco Telepresence systems, and physical access control devices
  • High availability for power and guaranteed uninterrupted services, a requirement for critical applications (e911)
  • Lowering OpEx by providing network resiliency at lower cost by consolidating backup power into the wiring closet
  • Faster deployment of new campus access networking infrastructures by eliminating the need for a power outlet for every endpoint

CCIE Data-Center:Transparent Inter-Connection of Lots of Links (TRILL)

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Transparent Inter-Connection of lots of hyperlinks (TRILL) is a generation that addresses the same necessities because the cloth route and has almost the identical blessings as fabric path.

The necessities and advantages of fabric course have been given within the fabric direction section of this chapter. The chapter on TRILL discusses all the boundaries of cutting-edge Layer 2 networking in element and how TRILL addresses them. TRILL, as of this writing, is an IETF well known.With the adjustments going on in the statistics middle environments, the modern-day STP has lots of dangers as mentioned right here:

Inefficient usage of hyperlinks: To avoid loops in a Layer 2 community, the STP ensures that there’s best one direction from a source to a destination. To reap this, the various hyperlinks in a transfer are installed a blocked state in order that data visitors doesn’t waft thru the links. 

With the speedy boom in server-to-server conversation, called east-west visitors, blocking off a few of the hyperlinks can purpose congestion in the hyperlinks which are in an unblocked nation. Shutting down or blocking the links in a switch reduces the value of a transfer that has the potential to host many ports able to wearing excessive-bandwidth site visitors. A Layer 3-like behavior is required, in which all of the hyperlinks in a switch can be used and that offers a loop-free mechanism.

long term to converge: STP isn't always designed for typologies which includes MSDC. The time taken for all the nodes in a network to go to a steady state is excessive. site visitors is disrupted till the consistent country is reached. 

whenever there may be a change in the topology due to a hyperlink going up or down or whilst new nodes are added or removed,spanning tree recalculation consequences in traffic disruption. honestly, a loop prevention mechanism is needed that could scale properly in an MSDC surroundings. once more, a Layer3 conduct is needed, wherein the routing protocol takes care of avoiding loops and also can scale to a large range of nodes.

Scaling the MAC desk: With the emergence of virtual machines, with every VM assigned a MAC deal with, the dimensions of the Layer 2 table can develop by a massive margin,in particular at the middle of the records center network that learns the MAC cope with of all the VMs. The price of the hardware may additionally growth with the increase inside the size of the hardware Layer 2 table. It’s most efficient to have a clean separation of the overlay network and the end host get right of entry to network such that the center network could have a Layer2 desk whose length may be better quantified by way of the range of switches in the overlay community than seeking to quantify the variety of cease host VMs in the complete community,which won't be a trivial undertaking. If the size of the Layer 2 table at the middle is less,it is able to bring about a few entries no longer being found out. this may result in a Layer 2 lookup leave out, that could result in a flood within the community. Flooding can devour pointless community bandwidth and can devour the CPU assets of the server due to the fact the server may also acquire the flood frames. genuinely, a tunneling protocol along with MAC-in-MAC is needed so that each one the middle switches do now not need to analyze all the stop host MAC addresses.

TRILL Requirement
Control protocol: TRILL uses Layer 2 IS-IS as its control protocol. The idea is to take the advantages of a Layer 3 routing protocol and at the same time maintain the simplicity of a Layer 2 network. Every node in a TRILL network is referred to as RBridge, aka Router-Bridge. Every R Bridge is identified by its nickname. In other words, a nickname is the routable entity in a TRILL network, just like an IP address in an IP network. 

Unlike Layer 3, there are no separate protocols for uni cast and multicast.The Layer 2-IS-IS protocol takes care of populating the routing table for uni cast
traffic, thereby ensuring multiple shortest equal cost paths (ECMPs) for all the RBridges and also creating trees for multicast traffic. Needless to say, Layer 2 IS-IS also ensures loop-free routing. But at the same time, TRILL inherits the TTL field from the Layer 3 world to ensure traffic due to intermittent loops eventually expires out.

Preserve plug-and-play features of classical Ethernet: One of the main advantages of a Layer 2 network is its plug-and-play nature, and the administrator is relieved of heavy configuration unlike in a Layer 3 network. TRILL achieves this with its Dynamic Resource Allocation Protocol (DRAP), where every node derives its own nickname and the protocol ensures there’s no duplicity. The configuration requirement of TRILL is minimal. 

Layer 2 table scaling: TRILL uses a MAC-in-MAC encapsulation, where the traffic from the host is encapsulated by the ingress RBridge. The core RBridges see only the outer MAC header, which has the MAC address of the source and destination RBridge. Consequently, the MAC table at the core RBridges will not be polluted with all the end host MAC addresses. 

TRILL Frame Format

 The ingress RBridge encapsulates the original Layer 2 frame with a new source and destination MAC, which are the MAC addresses of the source RBridge and the next-hop RBridge respectively; a TRILL Header, which has the Ingress and Egress nickname that identifies the source and destination RBridge, respectively; and the original Layer 2 frame with a new CRC. The incoming 802.1q or q-in-q tag needs to be preserved in the inner header.

TRILL Data Plane Operation
To describe the high-level data path operation,By now you would have already figured out that the forwarding is similar to Fabric Path.To describe the data path from Host 1 to Host 2, assume that all the control plane information has already been learned. Host 1 and Host 2 already know about each others MAC addresses. The basic steps involve the encapsulation of the frame with the TRILL header at the ingress RBridge, followed by switching using the TRILL header in the TRILL network and then finally de-capsulation of the frame at the egress RBridge. The following steps provide more details on this operation.

Host 1 uses its MAC address of A as the source MAC (SMAC) and sends a classical Ethernet frame, which is destined to Host 2 with a destination MAC (DMAC) address of B. On receiving this frame, the ingress RBridge (Nickname 10) does a (VLAN, DMAC) lookup. The MAC lookup points to the destination (Nickname 20) as the egress RBridge for this Ethernet frame. 

Fig 1.1- TRILL

So the ingress switch encapsulates this frame using the TRILL header for forwarding the frame to the TRILL core port. The source and destination nicknames are set as 10 and 20, respectively. The outer DMAC is the MAC address of the next-hop RBridge, and the outer SMAC is the MAC address of the source RBridge. 

The core RBridge (Nickname 30 in this example) forwards the frame based on the best path to the destination RBridge Nickname 20. In this case there are two paths to reach the egress RBridge with Nickname 20, but the best path is a directly connected link; therefore, the packet is forwarded over the directly connected interface to the switch with Nickname 20. 

The TTL is decremented, and the outer SMAC and DMAC are rewritten with the MAC address of this RBridge and RBridge 20’s MAC address. Just like regular IP routing, the TRILL header is not modified, but at each hop the router DMAC and SMAC are rewritten along with a TTL decrements. The destination RBridge 20 receives this frame. Because the incoming frame is destined to this RBridge, it removes the outer MAC and the TRILL header. It then forwards the frame to Host 2 based on the inner (DMAC and VLAN) lookup.

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