Aruba Switching

11. OSPFv2 Single Area

OPFv2 Router ID and Messaging OSPFv2 is the most popular option for corporations to route traffic within their networks. OSPF Introduction OSPF does not use UDP or TCP. OSPF advertisements are placed directly in an IP packet, therefore it does not have a TCP or UDP port number. It has IP protocol number 89. NOTE: The IP protocol number is…

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Aruba Switching

10 . IP Routing Part 3

Route Types and Administrative Distance Connected and Local Entries Connected: the subnet is physically connected to the switch and there is no need for a next hop device Local: the subnet is configured inside the switch. This could be a loopback interface or Switch Virtual Interface (SVI). Static Routes You need a static route when the destination network is not…

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Aruba Switching

9. IP Routing Part 2

Subnetting IPv4 Address Classes The IPv4 address space is divided into 5 classes (A to E) each of which is designed for a particular purpose. Class A: the first octet is between 0 and 127. The first octet (8 bits) is reserved for the network ID which means 3 octets (24 bits) are available for hosts on the network Class…

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Aruba Switching

8. VRRP (Virtual Router Redundancy Protocol)

An endpoint may only have one DG (Default Gateway), and a single DG means a single point of failure. In this example, if Core-1 is the DG for PC-1 and Core-1 fails, PC-1 and any other endpoints using Core-1 as the DG will be isolated. You could add another DG for redundancy, but you would have to somehow change the…

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Aruba Switching, Technology

7. IPv4 Routing Part 1

Routing IP routing connects VLANs together and routes packets between them. Routing devices use Layer 3 packet analysis to forward L3 packets. Layer 2 switches forward frames among devices in the same LAN by processing Layer 2 headers.  This is based on destination MAC addresses. Layer 3 devices move packets between LANs based on Layer 3 IP addresses. Routing Layer…

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6. Link Aggregation

Link Aggregation Without link aggregation, if you used two links to connect two switches together, the two links would create a loop and STP would automatically block one of the ports. Link Aggregation fixes this issue by bundling multiple physical interfaces into a single logical interface. Since STP sees this as a single interface there is no blocking.    …

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5. Spanning-Tree Protocol

Redundancy In the above example on the left, if Core 1 fails then the network is down and client A won’t be able to communicate with client B. In the example on the right, if Core 1 fails the network will say up as Core 2 is available and the Client can communicate through this. While this mitigates a single…

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Aruba Switching

4. VLANS

VLANS VLANs are used to isolate endpoints so you have better control over the traffic Default VLAN is VLAN 1 Devices in the same VLAN can communicate without routing.   Collison Domains On a Layer 1 Hub, only one ethernet host on a particular segment may transmit at a time, otherwise there is a collision. This is controlled by an…

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