Ethernet protocol

Ethernet

1. page 1
Ethernet Protocols

2. page 2
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.1344E-SPRing Ethernet Ring Protection Switch
ITU-T G.8261/Y.1361Timing and synchronization aspects in packet networks
IEEE 1588v2 Synchronization Protocol (PTP) in packet networks
Ethernet Protocols & Main Functions

3. page 3
IEEE Standards

4. page 4
Frame formats for Ethernet and IEEE 802.3

5. page 5
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

6. page 6
DSLAM
PC
ATU-R
ATM
Bay Networks
Bay Networks
BRAS
ATM
Switch
ATM
Switch
1483
Ethernet
ATM
ADSLPHYPHY
EthernetEthernet
ATM
ADSL
ATM
STM-1
1483
Ethernet
ATM
STM-1 PHY
Ethernet
ADSL ATM
ATM
PPPoE
PPP
IP
PPPoE
PPP
IP
PVC PVC
Protocols of ATM DSLAM

7. page 7
Protocols of IP DSLAM
DSLAM
PC
ATU-R
IP
BRAS
Router
1483
Ethernet
ATM
xDSLPHYPHY
EthernetEthernet
PHY
Ethernet
xDSL Ethernet
PPPoE
PPP
IP
PPPoE
PPP
IP
PVC
1483
Ethernet
ATM
xDSL PHY
Ethernet
Router
Ethernet

8. page 8
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

9. page 9
Find out the Root Bridge
which has lowest cost
and eliminate looping
Root
802.1d STP Principle

10. page 10
Bridge Architecture
802.1d STP Architecture

11. page 11
Operation of inter-bridge protocol
802.1d STP internal operation

12. page 12
Forwarding and Filtering flow chart
802.1d STP flow chart

13. page 13
Learning Process: Station A sends a frame to Station B
802.1d STP example

14. page 14
Complete Filtering Database is built, Station B sends a frame to Station C
802.1d STP example cont.

15. page 15
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

16. page 16
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.

17. page 17
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

18. page 18
LAN Segmentation

19. page 19
Types of VLANs
Tag-based VLAN
Untagged VLAN
- Port based
- MAC based
- Protocol based
- IP Subnet based

20. page 20
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.

21. page 21
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,….

22. page 22
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

23. page 23
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

24. page 24
Port-based VLAN (4)
1
2
4
3
5
7
6
8
9
Ethernet
DSL 1
DSL 2
DSL 3
DSL 4
DSL 5
DSL 6
DSL 7
DSL 8
Port-based configuration for 8 DSL ports IP DSLAM
example of port filter configuration
Port Egress Port
Ethernetall
DSL 1 E
DSL 2 E
DSL 3 E
DSL 4 E
DSL 5 E
DSL 6 E
DSL 7 E
DSL 8 E

25. page 25
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.
802.1
p
802.1
q
810
0

26. page 26
How 802.1Q VLAN works (1)

27. page 27
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.

28. page 28
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

29. page 29
Filtering Database
Dynamic VLAN (DVLAN) table
How 802.1Q VLAN works (4)

30. page 30
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.
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

31. page 31
How 802.1Q VLAN works (2)
example of PVID assignment

32. page 32
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.

33. page 33
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.

34. page 34
Normal, 802.1Q, and Double-Tagged Ethernet Packet Formats

35. page 35
Double Tagging -- IEEE 802.1Q (Tunneling)

36. page 36
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

37. page 37
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.

38. page 38
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.

39. page 39
Link Aggregation - Architecture

40. page 40
Link Aggregation sublayer block diagram

41. page 41
Link Aggregation Control Protocol (LACP)

42. page 42
Port Trunking & Fail-Over Function