Ethernet protocol

Ethernet Protocols & Main Functions Protocol & Standard Function IEEE 802.3u Fast Ethernet IEEE 802.3z Giga Bit Ethernet IEEE 802.1D STP (Spanning Tree Protocol) IEEE 802.1s MISTP (Multiple Instance STP) IEEE 802.1w RSTP (Rapid STP) IEEE 802.1p Priority Queuing, CoS IEEE 802.1Q VLAN (Port based, GVRP) IEEE 802.1ad VLAN (Q-in-Q) IEEE 802.1ah VLAN (MAC-in-MAC) IEEE 802.3ad Link Aggregation Control Protocol (LACP) IEEE 802.3x Flow Control and Back-pressure IEEE 802.3ah Ethernet OAM (Discovery, Event Notif, Loopback) IEEE 802.1ag Ethernet OAM (CFM) ITU-T/Y.1731 Ethernet OAM (CFM, PM) ITU-T G.8032/Y.1344 E-SPRing Ethernet Ring Protection Switch ITU-T G.8261/Y.1361 Timing and synchronization aspects in packet networks IEEE 1588v2 Synchronization Protocol (PTP) in packet networks

Frame formats for Ethernet and IEEE 802.3

Reserved MAC Addresses Dest. Address Assignment 01:00:5E:xx:xx:xx Group Dest. Addr. (GDA) FF:FF:FF:FF:FF:FF Broadcast Addr. 01:80:C2:00:00:00 BPDU (STP) 01:80:C2:00:00:01 Pause frame 01:80:C2:00:00:10 All LANs Bridge Management 01:80:C2:00:00:20 GMRP 01:80:C2:00:00:21 GVRP

802.1d STP The primary goals of Spanning Tree are as follows: Elimination of loops in a bridged infrastructure; Improved scalability in a large network; Provision of redundant paths, which can be activated upon failure. The Bridge Protocol exchanges Bridge Protocol Data Units (BPDUs) in Bridged LAN communication

Find out the Root Bridge which has lowest cost and eliminate looping Root 802.1d STP Principle

Bridge Architecture 802.1d STP Architecture

Operation of inter-bridge protocol 802.1d STP internal operation

Forwarding and Filtering flow chart 802.1d STP flow chart

Learning Process: Station A sends a frame to Station B 802.1d STP example

Complete Filtering Database is built, Station B sends a frame to Station C 802.1d STP example cont.

IGMP Overview Rather than Unicast and Broadcast, Multicast delivers IP packets to just a group of hosts on the network. IGMP (Internet Group Multicast Protocol) is a Network Layer protocol used to establish membership in a Multicast group Multicast IP address are Class D IP address, from 224.0.0.0 to 239.255.255.255 . They are also referred to as Group Destination Address ( GDA ). For each GDA, there is an associated MAC address. This GDA MAC address is formed by 01:00:5E:XX:XX:XX , followed by the latest 23 bits of the GDA multicast IP address in hex. For Example : GDA 224.10.10.10 corresponds to MAC address 01:00:5E:0A:0A:0A , GDA 239.255.255.255 corresponds to MAC address 01:00:5E:FF:FF:FF

IGMP Snooping A layer-2 switch supported IGMP snooping can passively snoop on IGMP Query, Report and Leave packets. It checks IGMP packets passing through it, picks out the group registration information, and configures multicasting accordingly. Without IGMP snooping, multicast traffic is treated in the same manner as broadcast traffic.

What is a Virtual VLAN? A VLAN is a switched network that is logically segmented on an organizational basis, by functions, project teams, or applications rather than on a physical or geographical basis. A VLAN can be thought of as a broadcast domain that exists within a defined set of switches. Why need implement VLANs ? • LAN Segmentation • Security • Broadcast Control • Performance • Network Management • Communication between VLANs

Types of VLANs Tag-based VLAN Untagged VLAN - Port based - MAC based - Protocol based - IP Subnet based

VLAN Classification When the switch receives a frame: If the frame is untagged , the switch classifies the frame to a port-based VLAN. VID is not concerned . If the frame is untagged , a port VLAN identifier (PVID) can be assigned for the port. Ingress traffic is associate with the PVID, and egress traffic is with VID . If the frame is tagged , the switch uses the tagged VLAN ID to identify the broadcasting domain of the frame.

Port-based VLAN (1) Easy to configure, define egress ports for each port. VLAN only governs the outgoing traffic, and unidirectional Port-based VLAN can't across different switches, but, … .

Port-based VLAN (2) Port Egress Port port 0 all port 1 all port 2 all port 3 all port 4 all port 5 all port 6 all

Port-based VLAN (3) Port Egress Port port 0 5 port 1 all except 0 port 2 all except 0 port 3 all except 0 port 4 all except 0 port 5 all port 6 all except 0

Port-based VLAN (4) example of port filter configuration Port Egress Port Ethernet all DSL 1 E DSL 2 E DSL 3 E DSL 4 E DSL 5 E DSL 6 E DSL 7 E DSL 8 E

Tag-based VLAN Overview TPID has a defined value of 8100 in hex. When a frame has the EtherType equal to 8100, this frame carries the tag IEEE 802.1P / 802.1P. VLAN ID has 12 bits and allow the identification of 4096 (2^12) VLANs. Of the 4096 possible VIDs, a VID of 0 is used to identify priority frames and value 4095 (FFF) is reserved, so the maximum possible VLAN configurations are 4,094. 802.1p 802.1q 8100

How 802.1Q VLAN works (2) Each physical port has a parameter called PVID. When a untagged frame is received, the PVID is assigned to it. for example, the two stations connected to the central trunk link in the lower part of Figure . They are VLAN-unaware and they will be associated to the VLAN C, because the PVIDs of the VLAN-aware bridges are equal to VLAN C.

How 802.1Q VLAN works (3) The Forwarding Process decide to forward the received frames according to the the Filtering Database The Filtering Database consists of static registration entries ( SVLAN table) and dynamic registration entries (DVLAN table). SVLAN table is manually added and maintained by the administrator. DVLAN table is automatically learned via GVRP protocol, and can't be created and upgraded by the administrator

Filtering Database Dynamic VLAN (DVLAN) table How 802.1Q VLAN works (4)

GVRP The GARP VLAN Registration Protocol (GVRP) defines a GARP Application that provides the VLAN registration service GVRP supports the dynamic registration of VLAN port members within a switch and across multiple switches. GVRP is used to communicate VLAN registration information to other VLAN-aware switches, so that members of a VLAN can cover a wide span of switches in a network. Physical Layer GARP Multicast Registration Protocol (GMRP) GARP VLAN Registration Protocol (GVRP) Generic Attribute Registration Protocol (GARP) Logical Link Control LLC SAP 0x42 Media Access Control Physical Layer

How 802.1Q VLAN works (2) example of PVID assignment

802.1ad Double Tagging IEEE 802.1ad Q-in-Q VLAN : The primary benefit for the service provider is reduced number of VLANs supported for the same number of customers. Other benefits of this feature include: PPPoE scalability. By expanding the available VLAN space from 4096 to approximately 16.8million (4096 times 4096 ) , the number of PPPoE sessions that can be terminated on a given interfaceis multiplied. When deploying Gigabyte Ethernet DSLAM in wholesale model, you can assign the inner VLANID to represent the end-customer virtual circuit (VC) and assign the outer VLAN ID to represent the service provider ID.

802.1Q Tunneling : Tunneling is a feature designed for service providers who carry traffic of multiple customers across their networks and are required to maintain the VLAN and Layer 2 protocol configurations of each customer without impacting the traffic of other customers. Using the 802.1Q tunneling feature, service providers can use only a single VLAN to support a customer who has multiple VLANs. The outer tag (metro tag) containing the VLAN ID unique to each customer 802.1ad Double Tagging - cont.

Normal, 802.1Q, and Double-Tagged Ethernet Packet Formats

Double Tagging -- IEEE 802.1Q (Tunneling)

The primary goals of Link Aggregation are as follows: - Increased bandwidth - Increased availability - Load sharing IEEE 802.3ad link aggregation enables you to group Ethernet interfaces at the physical layer to form a single link layer interface, also known as a link aggregation group ( LAG ) or Bundle. For example, if you need 450 Mbps of bandwidth to transmit data and have only a 100-Mbps Fast Ethernet link, creating a LAG bundle containing five 100-Mbps Fast Ethernet links is more cost effective than purchasing a single Gigabit Ethernet link. 802.3ad Link Aggregation

802.3ad Link Aggregation –cont. The Link Aggregation Control Protocol ( LACP ) is a mechanism for exchanging port and system information to create and maintain LAG bundles. The LAG bundle distributes MAC clients across the link layer interface and collects traffic from the links to present to the MAC clients of the LAG bundle. LACP that can be used for automatic communication of aggregation capabilities between Systems and automatic configuration of Link Aggregation.

Interface Stack for 802.3ad Link Aggregation After configure the LAG bundle, you can route IP traffic over it or create a VLAN over it. Figure below displays the interface stack for 802.3ad link aggregation.

Link Aggregation - Architecture

Link Aggregation sublayer block diagram

Link Aggregation Control Protocol (LACP)

Port Trunking & Fail-Over Function

Ethernet protocol

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