![Technologies Overview 12
VC parametersBit Rate
[Kbps]
Time
[sec.]
Bc+Be
Tc
CIR
Dicarded
DATA](https://image.slidesharecdn.com/06-frtechnology-030420-161127022931/85/06-fr-technology-030420-12-320.jpg)
![Technologies Overview 25
Physical Layer Parameters Configuration
• Data rate [n*64kbps]
• Protocol [v.35 / x.21]
• Operating mode [DCE / DTE]
• Timing mode [internal / external]
• Clock mode [standard / inverse]
• Administrative status [enable / disable]](https://image.slidesharecdn.com/06-frtechnology-030420-161127022931/85/06-fr-technology-030420-25-320.jpg)
![Technologies Overview 26
Protocol Parameters Configuration
• Signaling protocol [ ansit1617annexd / ccitt AnnexA /
LMI]
• Port type [UNI / NNI]](https://image.slidesharecdn.com/06-frtechnology-030420-161127022931/85/06-fr-technology-030420-26-320.jpg)
![Technologies Overview 27
Service Parameters Configuration
• DLCI [16 ..995]
• Cir/Bc/be [0..4095, 0..4095, 0..4095] kbps
• BS port number [0/1/2]
• TS customer ID
• TS port number [0/1/2]
• Administrative status [enable/disable]](https://image.slidesharecdn.com/06-frtechnology-030420-161127022931/85/06-fr-technology-030420-27-320.jpg)
![Technologies Overview 33
Adding FR service (cont’)
• Stage 3:
Adding the DLCI and the connection
• DLCI [16 .. 995]
• Cir/Bc/Be [0..4095, 0..4095, 0..4095] kbps
• BS port number [0/1/2]
• TS customer ID
• TS port number [0/1/2]
• Administrative status [enable/disable]](https://image.slidesharecdn.com/06-frtechnology-030420-161127022931/85/06-fr-technology-030420-33-320.jpg)
06 fr technology-030420
- 2. Technologies Overview 2 Frame Relay History • Before frame relay era, large organizations were interconnected by: X.25 Leased Lines Long network processing time Point to point connectivity Low bandwidth (max. 64kbps) Expensive, there is no Charge per traffic bandwidth sharing Required multiple port routers Fixed price
- 3. Technologies Overview 3 Frame Relay History • As the 1980’s came to close a new demands from the wide area network switching began to appear: • Growth in high speed, high speed throughput application. • Sophistication of the end user devices, equipment with processing ability. • This new wide area switching technology required high speed, low delay, port sharing and bandwidth sharing on a virtual circuit basis. • These characteristics implemented in Frame Relay make Frame Relay ideal solution for the burst traffic sources found in LAN-WAN internetworking.
- 4. Technologies Overview 4 What is Frame Relay? • Frame Relay is a high-speed communication technology, which enables to send information over the WAN by dividing the information into frames and packets. • Frame Relay is not a single physical connection between two end points, but a logical path is defined within the network.No Bandwidth is allocated to the path until actual data needs to be transmitted. Then, the Bandwidth within the network is allocated on a packet-by-packet basis, This logical path called VC (Virtual Circuit).
- 5. Technologies Overview 5 E C A Router Router Router Frame Relay Network DLCI101 DLCI102 DLCI103 LAN 1 LAN 2 LAN 3 D B Frame Relay Network
- 6. Technologies Overview 6 Frame Relay Network (cont.) User Node Router User Node Router User Node Router User Node Router FR switch Network Node FR switch FR switch NNI Network to Network Interface UNI User to Network Interface • Network nodes (FR switches) • User nodes (usually routers)
- 7. Technologies Overview 7 Data Link Control Identifier • Logical connection with pre-defined bandwidth from 56KBps to E1/T1 and even T3 • Many logical connections can co-exist on a single physical line • DLCI no. is attached to data frames in order to tell the network how to route the data
- 8. Technologies Overview 8 VC Parameters • Each VC has several parameters needed to be configured: • CIR (Committed Information Rate) • CIR is the "worst-case" throughput that the frame relay network provider attempts to guaranty • CIR bandwidth is guaranteed. In overload situations, transmission will occur over a reasonable time span (usually over a span of seconds) • Transmission is monitored using "leaky bucket algorithm." • Bc (Burst Committed) • Value which indicated how many bits can be transmitted at a certain time interval and the system obligate to transmit them. • Be (Burst Exceeded) • The amount of bits which were transmitted over the Bc at the defined time interval. • Tc (Time Committed) • The time interval.
- 9. Technologies Overview 9 Leaky Bucket Algorithm • When buying a CIR, one is getting a timed buffer (bucket) in each switch port along the PVC. This bucket has two dimensions: • A diameter measured in seconds called committed time (Tc) • A height called committed burst (Bc) measured in Kbytes • One can only send Bc frames or less during every Tc period (CIR = Bc/Tc) • The power of Frame Relay consists in a second bucket: its diameter is also Tc. Its height is typically equal to Bc and is known as excess burst (BE) - (for CIR=0 excess rate =Be/Tc)
- 10. Technologies Overview 10 Leaky Bucket Algorithm (cont.) Bc+BeBc
- 11. Technologies Overview 11 VC Parameters To To+Tc Time Bits Bc+Be Bc Access Rate CIR Frame 1 within CIR Frame 2 within CIR Frame 3 within CIR Frame 4 marked DE Frame 5 Discarded
- 12. Technologies Overview 12 VC parametersBit Rate [Kbps] Time [sec.] Bc+Be Tc CIR Dicarded DATA
- 13. Technologies Overview 13 Frame Relay Packet Structure • Frame Relay Header: 2 bytes of FR address and control • Information Field: User’s data • FCS: 32 bits of Cyclic Redundancy Check (CRC) • Flag : 2 identical bytes made of 6 ones and 2 zeros.
- 14. Technologies Overview 14 Frame Relay Theory • Congestion Notification Mechanism is helping us to avoid a situation where a node reaches a certain point which it can’t deliver data any more due to a sever congestions. In Frame Relay there are several ways to avoid congestions: • Explicit Congestion Notification • Discard Eligibility
- 15. Technologies Overview 15 • Explicit Congestion Notification Congestion FECN – Forward Explicit Congestion Notification BECN – Backward Explicit Congestion Notification C B A Router Router Frame Relay Network LAN 1 LAN 2 Frame Relay Theory
- 16. Technologies Overview 16 Frame Relay Theory • Discard Eligibility • Due to the use of the CIR which is an obligation for the quality of service to the customer, in case of a problem any frame which is send through the network above the CIR can be discarded. And will not effect the guarantied Quality of Service.
- 17. Technologies Overview 17 Frame Relay Theory • Local Management Interface (LMI) • The LMI is a connection status mechanism, this status information is accomplished on unique DLCI using special management frames. • The management frames monitors the status of the connection and provide the following information: • Weather the interface is still active. • The valid DLCIs defines in the interface. • The status of each VC (Congested or not, etc.). • There are 3 versions of LMI specifications: • LMI – Defined by the Frame Relay Forum. • Annex A – Defined by ITU-T(CCITT). • Annex D- Defined by ANSI.
- 18. Technologies Overview 18 Frame Relay Advantages • Frame Relay benefits over alternative technologies: • Lower cost of ownership • Well-established and widely adopted standards that allow open architecture and plug-and-play service implementation. • Low overhead, combined with high reliability. • Network scalability, flexibility and disaster recovery. • Interworking with other new services and applications, such ATM.
- 19. Frame Relay Technology in WALKair 1000
- 20. Technologies Overview 20 Frame Relay traffic parameters • Committed Information Rate (CIR) • The bandwidth defines for a VC. • Bc = Burst Committed • Maximum number of committed bits to be transmitted over time interval (Tc). • Be = Burst Excess • Number of excess bits that will be transmitted over time Interval (Tc). • Tc = Time interval • Time measurement based on the amount of bandwidth is available for data to burst on to the network. For better performance it is recommended that the TC will be 1/8 sec.
- 21. Technologies Overview 21 Data Flow in WALKair HDLC DRIVER DLCI 16 DLCI 17 CIRCIR EXSEXS TX Q DATA TRANSMITTED OVER THE AIR WALKair Congestion Ind. WALKair DATA RECEIVED FROM THE AIR RX Q HDLC DRIVER DATA to FR DEVICE DATA from FR DEVICE
- 22. Technologies Overview 22 Relay BS TS TS FRAD FRAD FR switch FRAD m*DLCI's max(m)=200 n*DLCI's max(n)=30 Frame Relay Network DLCI 101 DLCI 102 FR switch
- 23. Technologies Overview 23 Frame Relay DLCI 20 FR Networ k BS TS1 TS2 FRAD FRAD FR switch FR switch FRAD DLCI 17 DLCI 18 DLCI 18 DLCI 17 DLCI 19 DLCI 19 10BaeT 10BaeT
- 24. Technologies Overview 24 Congestion Notification TSBS Uplink Congestion TS congested with traffic towards the air link FR Switch Router BS congested with traffic towards the FR switch TSBS Downlink Congestion BS congested with traffic towards the air link FR Switch Router TS congested with traffic towards the FR router
- 25. Technologies Overview 25 Physical Layer Parameters Configuration • Data rate [n*64kbps] • Protocol [v.35 / x.21] • Operating mode [DCE / DTE] • Timing mode [internal / external] • Clock mode [standard / inverse] • Administrative status [enable / disable]
- 26. Technologies Overview 26 Protocol Parameters Configuration • Signaling protocol [ ansit1617annexd / ccitt AnnexA / LMI] • Port type [UNI / NNI]
- 27. Technologies Overview 27 Service Parameters Configuration • DLCI [16 ..995] • Cir/Bc/be [0..4095, 0..4095, 0..4095] kbps • BS port number [0/1/2] • TS customer ID • TS port number [0/1/2] • Administrative status [enable/disable]
- 28. Technologies Overview 28 Frame Relay Attributes in WALKair • DLCI • 979 DLCI(s) with 2 octets long • Same set at BS and TS's • Maximum DLCI(s) per TS port is 30 • Maximum DLCI(s) per BS’BU port is 250 • CIR • CIR (BS port) = CIR (all TS’s) <= 2mbps/4mbps • Recommendation: TS_CIR to be a boundary of n*64 kbps • BC=CIR/8 ; BE=(MIR-CIR)/8
- 29. Technologies Overview 29 Management Protocol Configuration • WALKair supports all the relevant items of frame relay NNI MIB RFC 1604, including all statistic information. • Traps will be send to the EMS whenever there is a change in the operational status in 3 levels: • Physical link (up or down). • FR port (up or down). • DLCI (up or down).
- 30. Certified Alvarion System Engineer - CASE Frame Relay Technology
- 31. Technologies Overview 31 Adding FR service • Stage 1: • Configure the telecom port (physical layer) both in the BS and TS.
- 32. Technologies Overview 32 Adding FR service (cont’) •Stage 2: •Configure the Logical Port: Signaling protocol •ANSI 1617 Annex D •CCITT Annex A •LMI Port type •U-UNI •N-NNI •T-UNI From the FR interface menu add interface
- 33. Technologies Overview 33 Adding FR service (cont’) • Stage 3: Adding the DLCI and the connection • DLCI [16 .. 995] • Cir/Bc/Be [0..4095, 0..4095, 0..4095] kbps • BS port number [0/1/2] • TS customer ID • TS port number [0/1/2] • Administrative status [enable/disable]
- 34. Technologies Overview 34 Adding FR service (cont’)