Media Access Control Address (MAC)

We can configure VLAN statically# and dynamically (using Network Management System (NMS)#, grouping based on the Media Access Control Address (MAC) of the device).

It has three primary frame switching modes: Cut-Through Switching#, Store-And-Forward Switching# and Fragment-Free Switching#. All of them will check the destination and source Media Access Control Address (MAC), then check against the table, which contains entries that map Switch port to a particular MAC, maintained by Switch. It will place an entry for the source MAC corresponds to the switch port where the frame came (if it hasn’t done so before), and check whether there is an entry for the destination MAC. If there is not, it will flood (send frames to all other ports) the frames, and waits for the response. If there is such a response coming from one of the switch’s port, it will map that port to the destination MAC and immediately forward the packet to the port. Otherwise, depending on whether the destination MAC is in the same network segment, it either doesn’t forward the packet or forward the packet to the port specified in the table (filtering).

The process of forwarding the packet from its received port to the outgoing port is called switching. Despite the naming, Router will immediately drop the packet when it can’t figure the destination in its routing table maintained by itself. Otherwise, it will simply modify the destination Media Access Control Address (MAC) (the next-hop, can be another Router or the final destination) in the packet without touching the IP Address which defines the final destination. Though the primary forwarding decision will be based on the Routing Table# or routing information, assuming there is a mapping of logical address to its interface or port. If there is no path defined in the routing table to where the packet should be forwarded to, Router will redirect it to a default route if set (usually 0.0.0.0 in IPv4 Address and ::/0 in IPv6 Address), or simply discards it and sends Internet Control Message Protocol (ICMP)# Unreachable message to the source. Additionally, we can divide a physical interface into at most 65,535 logical interfaces using the command interface {interface-name} {interface}.{subinterface}. This is particularly useful in Virtual LAN (VLAN) routing.

The functionality of RARP is the exact reverse of Address Resolution Protocol (ARP), that is to map Media Access Control Address (MAC)# to IPv4 Address#. It is especially useful for a diskless host to obtain a valid IP address from its server.

Network Loop could happen when there is a redundancy within the network, especially in 202207051851# and 202207051907# network. The packet could be trapped in a circle where they will travel endlessly around the same path. As more and more packets get involved in the loop, the network will inevitably come to a halt as no more bandwidth is available to the hosts due to broadcast-storms (infinite flooding of frames originally for broadcasting), multiple copies of frames (most protocols can’t handle duplicated transmissions), and 202206151451 address table instability (receiving the same frame on different ports).

Other than that, there are some differences between Version 5 and Version 4#. Firstly, Version 4 depends solely on the use of Data Encryption Standard (DES) whereas Version 5 accepts any kind of encryption scheme or technique. Furthermore, V4 requires the use of IP Address# only whereas V5 allows any type of network address such as Media Access Control Address (MAC)# to be used. In V4, the sender of the message could choose its own message byte ordering, but the message structure is standardised using Abstract Syntax Notation One (ANS.1) and Basic Encoding Rules (BER) in V5. Moreover, the ticket lifetime is now indicated using explicit start and end time in V5, in contrast to the encoded 8-bit lifetimes values (up to 1280 minutes) in V4. Additionally, authentication forwarding is allowed in V5, but it is not in V4. Last but not least, the interopability (the degree of two things could be used together) among \(N\) realms requires \(O(N^2)\) Kerberos-to-Kerberos relationships in V4. V5 has a method that requires fewer relationships than in V4.

An IP Address is a network address that is assigned by the local network using #Internet Protocol (IP). Unlike Media Access Control Address (MAC), it is temporary and can be easily changed. In the local network, the IP address must be unique.

One can find a device by using either 202206151451# or 202206151453#.

Data Link layer is the second layer for #Open Systems Interconnection (OSI) Model. It is referred as Link Layer together with Physical Layer in #Internet Protocol Suite (TCP/IP). Its responsibility is to establish a communication session between two different devices at node level regardless of network types. It will encapsulate# the data with a header that includes the information about the protocol used and the source and destination Media Access Control Address (MAC)#. All Ethernet switching and bridging are done here. Its #Protocol Data Units (PDU)# is a frame.

Cut-Through Switching, aka fast-forward switching, is a kind of #switching mode that immediately forwards the frame received after the check on destination 202206151451#. Latency is not a problem, but in this mode, frames errors will be easily transmitted to other network segments.

Authenticity is a quality of how true or authentic the entity is the one as claimed. There are several threats to Authenticity such as physical access to authenticated device, impersonation of authenticated device by masking its Media Access Control Address (MAC) (Masquerade), and gaining entrance to server or disrupting operations with Replay Attack. This could be avoid with cryptographic techniques.

ARP is responsible for mapping IPv4 Address# to Media Access Control Address (MAC)#. See Reverse Address Resolution Protocol (RARP) for the reverse mapping. Typically, it is used on broadcast networks such as Ethernet#, Token Ring, and FDDI.