Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Carrier Ethernet course

712 views

Published on

MEF-CECP exam preparation course.

Published in: Technology
  • Be the first to comment

Carrier Ethernet course

  1. 1. Carrier Ethernet Agenda of Day 1  Introduction to Carrier Ethernet  MEF Services  CE Fundamentals  Service Attributes  Questions / Review Day 1 1
  2. 2. Carrier Ethernet Agenda of Day 1  Introduction to Carrier Ethernet  MEF Services  CE Fundamentals  Service Attributes {MEF 6.2, MEF 10.3, MEF 13, MEF 20, MEF 26.2}  Questions / Review Day 1 54
  3. 3. Defining MEF Services MEF Services MEF Service Type UNI, EVC, & UNI/EVC attributes associated with MEF Service Type Values for each of the UNI/EVC attributes associated with MEF Service Type MEFStandardized:EthernetServicesDefinitionFramework E-Line / E-LAN / E-Tree Defined by Defined by Defined by Traffic Parameters(BW Profile) Ethernet Physical Interface Service Frame Delivery VLAN Tag Support Service Multiplexing Bundling EVC Performance Etc. …. Actual values of above parameters to ultimately define MEF Services. NOTE: Some of these attributes are applicable to UNI, others to EVCs, & still others to both UNI & EVCs. 55Note: E-Access service is not shown here due to OVC-based service nature.
  4. 4. Service Attributes Three categories of service attributes are associated with a particular MEF service.  service attributes applicable to particular UNI only.  service attributes applicable to EVC as a whole.  service attributes applicable to particular EVC at a particular UNI. Service Attributes UNI Service Attributes EVC Service Attributes EVC per UNI Service Attributes  Next slide displays comprehensive list of service attributes belonging to each category.  Assuming there is only one MEN involved which is operated by Service-Provider. 56
  5. 5. List of Service Attributes UNI Service Attributes EVC per UNI Service Attributes EVC Service Attributes UNI Identifier UNI EVC ID EVC Type Physical Medium CE-VLAN ID / EVC Map EVC ID Speed Ingress Bandwidth Profile Per EVC UNI List Mode Ingress Bandwidth Profile Per CoS Identifier Maximum Number of UNIs MAC Layer Egress Bandwidth Profile Per EVC EVC MTU size UNI MTU Size Egress Bandwidth Profile Per CoS Identifier CE-VLAN ID Preservation Service Multiplexing CE-VLAN CoS Preservation Bundling Unicast Service Frame Delivery All to One Bundling Multicast Service Frame Delivery CE-VLAN ID for untagged and priority tagged Service Frames Broadcast Service Frame Delivery Maximum number of EVCs Layer 2 Control Protocol Processing (only applies for L2CPs passed to the EVC) Layer 2 Control Protocols Processing EVC Performance Ingress Bandwidth Profile Per UNI Egress Bandwidth Profile Per UNI 57
  6. 6. UNI Service Attributes Here is the list of UNI Service Attributes.  UNI Identifier  Physical Medium  Speed  Mode  MAC Layer  UNI MTU Size  Service Multiplexing  Bundling  All to One Bundling  CE-VLAN ID for untagged & priority-tagged Service Frames  Maximum Number of EVCs  Layer 2 Control Protocols Processing  Ingress Bandwidth Profile per UNI  Egress Bandwidth Profile per UNI Service Attributes UNI Service Attributes EVC Service Attributes EVC per UNI Service Attributes Ethernet Physical Interface  The listed items may vary depending on service type in question ! 58
  7. 7. UNI Service Attributes: Ethernet Physical Interface Physical Medium: • Any one of the following IEEE 802.3 Ethernet PHYs can be used:  10BASE-T  100BASE-T including 100BASE-TX & 100BASE-FX  1000BASE-X including 1000BASE-SX, 1000BASE-LX, & 1000BASE-T  10GBASE-SR, 10GBASE-LX4, 10GBASE-LR, 10GBASE-ER, 10GBASE-SW, 10GBASE-LW, & 10GBASE-EW Speed: • 10 Mbps, 100 Mbps, 10/100 Mbps Auto-Negotiation, 10/100/1000 Mbps Auto- Negotiation, 1 Gbps, or 10 Gbps. Mode: • Full Duplex (FDX) MAC Layer: • IEEE 802.3 - 2005 59
  8. 8. UNI Service Attributes UNI Identifier: • Arbitrary text string to identify the UNI. • Examples: U1, U50 etc. • More practical example is like; “KRPOP1-Node2-Slot2-Port4" which signify Port 4 in Slot 2 of Node 2 in Karachi POP1. UNI MTU Size: • The maximum sized Service Frame allowed at the UNI. • Must be ≥ 1522 bytes (1518 + 4) • A similar attribute “EVC MTU Size” belongs to EVC Service Attributes. 60 What is Jumbo Frame?
  9. 9. UNI Service Attributes: Service Multiplexing, Bundling, All- to-One Bundling Service Multiplexing: • Ability of UNI (a physical interface) to support multiple EVCs and precludes the need for a separate UNI to support each EVC. Bundling: • Allows two or more CE-VLAN IDs to be mapped to a single EVC at a UNI. (Multiple CE-VLAN IDs per EVC but multiple EVCs per UNI) All-to-One Bundling: • An UNI attribute in which all CE-VLAN IDs are associated with a single EVC. (Only ONE EVC per UNI) • All-to-One bundling is required in order to support private services (EPL, EP-LAN, or EP-Tree). In such a setting, there is a single EVC at the UNI and all service frames are mapped to this EVC.  What if I have only ONE CE-VLAN ID mapped to an EVC of an EPL, can I say “All-to-One- Bundling” = Yes? 61
  10. 10. UNI Service Attributes: Service Multiplexing, Bundling, All- to-One Bundling • All-to-One-Bundling and Bundling can never be YES at the same time (Mutually Exclusive). • All-to-One-Bundling is a sub set of Bundling (special case). • CE-VLAN ID Preservation should always be set to YES when either Bundling or All-to- One-Bundling is YES. • If Bundling or All-to-One-Bundling is YES, CE-VLAN ID Preservation must be YES. NOTE: All-to-One Bundling is applicable ONLY to port-based MEF services. (EPL, EP-LAN, EP- Tree) Bundling may exist in VLAN-based MEF services. (EVPL, EVP-LAN, EVP-Tree) Service Multiplexing NOT possible in port-based MEF services. (EPL, EP-LAN, EP-Tree) Service Multiplexing may exist in VLAN-based MEF services. (EVPL, EVP-LAN, EVP- Tree) {should exists in most cases} 62
  11. 11. Question: All-to-One Bundling All-to-One Bundling is NOT applicable to which of the following MEF service. (select one) a) EPL b) EVPL c) EP-LAN d) EP-Tree e) None of Above 63 Answer b) EVPL
  12. 12. Five valid combinations of Service Multiplexing, Bundling, & All-to-One Bundling Valid Combination 1: Service Multiplexing = No Bundling = No All-to-One Bundling = No Example: EVPL having ONE EVC with ONE CE-VLAN ID mapped to the EVC. Valid Combination 2: Service Multiplexing = Yes Bundling = No All-to-One Bundling = No Example: EVPL having multiple VLAN-based EVCs with only ONE CE-VLAN ID mapped to each EVC. Valid Combination 3: Service Multiplexing = Yes Bundling = Yes All-to-One Bundling = No Example: EVPL having multiple VLAN-based EVCs with two or more CE-VLAN IDs mapped to each EVC. 64
  13. 13. Five valid combinations of Service Multiplexing, Bundling, & All-to-One Bundling Valid Combination 4: Service Multiplexing = No Bundling = Yes All-to-One Bundling = No Example: EVPL having ONE VLAN-based EVC with two or more CE-VLAN IDs mapped to it. Valid Combination 5: Service Multiplexing = No Bundling = No All-to-One Bundling = Yes Example: EPL having one port-based EVC with all service frames mapped to the EVC. 65
  14. 14. UNI Service Attributes CE-VLAN ID for Untagged & Priority-tagged Service Frames: • A Service Frame consists of the first bit of the Destination MAC Address through the last bit of the Frame Check Sequence. • Priority-Tagged service frames are those whose VLAN ID is “0”. • Untagged service frames are L2CP frames except some L2CPs like STP/ PVSTP etc. • CE-VLAN ID for untagged & priority tagged Service Frames must be in the range of 1- 4094. • This attribute is not required for port-based services. (when “All-to-One Bundling=Yes”) • Since the UNI is dedicated to a single Subscriber, only one Subscriber can access the EVCs at the UNI. MEN / CEN Stacking Tagging tag w/o tag w tag w/o tag double tag w tag tagged tagged double tag w tag tagged tagged tag w tag w/o tag w/o tag LAN LAN 66 NID NID Traffic Direction
  15. 15. UNI Service Attributes Maximum number of EVCs: • This attribute defines the maximum number of EVCs that the UNI can support. • It must have a value of at least one (like in case of Port-based services). • Chart below shows the difference among Tagging, Stacking, & Stripping. • Stripping is exact opposite of Stacking. Ingress Egress Tagging ETH Frame ETH Frame + VLAN TAG ETH Frame + VLAN TAG ETH Frame + VLAN TAG Stacking ETH Frame ETH Frame + VLAN TAG ETH Frame + VLAN TAG ETH Frame + VLAN TAG + VLAN TAG Stripping ETH Frame + VLAN TAG + VLAN TAG ETH Frame + VLAN TAG ETH Frame + VLAN TAG ETH Frame 67
  16. 16. UNI Service Attributes: Layer 2 Control Protocol Processing • L2CP frames are recognized on the basis of their destination MAC Addresses.  01-80-C2-00-00-00 through 01-80-C2-00-00-0F (Bridge Block of Protocols)  01-80-C2-00-00-20 through 01-80-C2-00-00-2F (GARP Block of Protocols) • Examples of L2CPs are STP, PAUSE (used for flow control 802.3x), LACP / LAMP, Link OAM, Port Authentication (802.1x), E-LMI, LLDP, GARP / MRP. • Refer MEF 6.2 / MEF 10.3 for detailed information on handling L2CPs. (along with complete L2CP list) • In case of identical MAC Address of L2CPs, another field “Ether Type” help in recognizing frame type. • For “UNI service attribute of L2CP Processing”, one of the following options should be specified:  Peer (CEN will participate in the protocol)  Discard (CEN will ignore the L2CP frame which means that it will neither participate in the protocol nor it will forward the frame)  Pass to EVC  Peer & Pass to EVC 68 Refer EVC Service Attribute “L2CP Processing” for further outcome. Don’t bother looking at EVC Service Attribute “L2CP Processing”.
  17. 17. BW Profile (Traffic Parameters CIR, CBS, EIR, EBS) • Bandwidth Profile is one of the “UNI” or “EVC per UNI” attributes defined during provisioning of MEF service. • Bandwidth Profile is a characterization of Ethernet frames (e.g. frames from a customer into a UNI) • Bandwidth Profile consists of 4 traffic parameters; 1. Committed Information Rate (CIR) – SLA based 2. Committed Burst Size (CBS) – SLA based 3. Excess Information Rate (EIR) – not subject to SLA & optional 4. Excess Burst Size (EBS) – not subject to SLA & optional • BW Profile should be applied at Ingress node (applying at Egress node is optional);  Ingress Bandwidth Profile per UNI (part of UNI service attributes)  Ingress Bandwidth Profile per EVC (part of EVC per UNI service attributes)  Ingress Bandwidth Profile per CoS Identifier (part of EVC per UNI service attributes) • Multiple services can be offered over a subscriber UNI & each of these services can have its own Bandwidth Profile. 70
  18. 18. Bandwidth Profile Visualization  SLAs are based on CIR/CBS (Green Service Frames only) 71 Traffic Stream Tokens flow into the bucket at a constant rate The size of the token bucket reflects the maximum burst size Each Service Frame needs one token per byte If token bucket fills, excess tokens are discarded. Constant Rate Burst Size Single Rate Scenario Two Rate Scenario Traffic Stream CIR/8 CBS EIR/8 EBS
  19. 19. UNI Service Attributes: Ingress / Egress BW Profile per UNI UNI-N EVC 1 Ingress BW Profile per UNI • Can not be used for port based MEF services since “Ingress BW Profile per UNI” would be same as “Ingress BW Profile per EVC”. • Port based services (e.g. EPL) would always use “Ingress BW Profile per EVC” to avoid duplication. (“Ingress BW Profile per CoS ID” can be used though) • For all BW Profile types, EIR & EBS are based on available BW (non SLA). • Should the value of CIR be kept same on both ingress UNIs of an EPL service? How about Asymmetric bandwidth in uplink and downlink directions? UNI-N EVC 2 Egress BW Profile per UNI EVC 1 EVC 2 72
  20. 20. Bandwidth Profile Facts • At Egress, Bandwidth Profile is optional but un-necessary in case of EPL & EVPL. • CBS & EBS should have higher values at Egress than Ingress in case of E-LAN services. Higher EBS and CBS can bear burstiness caused within MEN (or CEN). • “Ingress BW Profile per UNI” & “Ingress BW Profile per EVC” are same in case of port based services like EPL, EP-LAN, EP-Tree. Therefore in order to avoid duplication, “Ingress BW Profile per UNI” is not used & only “Ingress BW Profile per EVC” is used. (MEF 6.2, Table 10) • Sum of all CIRs associated with EVCs should be less than UNI speed (Layer 1 bytes). • If CIR=0 and EIR=“some value” then it means only “best effort” traffic is allowed. • It is prohibited to implement more than one BW Profile types which may overlap each other’s services. • BW Profile helps eliminate burstiness of customer traffic from spreading into Service Provider network. • It allocates desirable green and/or yellow traffic speed(s) for customers as per SLA. • Peak Information Rate = EIR + CIR • Any advantage of applying CIR / EIR at Egress? 73
  21. 21. Color Marking (Rate Enforcement) • Rate enforcement applied via two-rate (double stage consists of Committed & Excess) states. • Three Color Marker (TCM) algorithm (Green, Yellow, Red) implemented as Token Bucket. • GREEN Traffic:  Everything below CIR. All performance metrics guaranteed by SLA.  A Green Frame can not be converted to Yellow inside MEN under any circumstances. • YELLOW Traffic:  Everything between CIR and EIR (above CIR & below EIR)  Yellow traffic accepted only if network capacity permits (without any performance guarantee)  Drop Eligible traffic (Best Effort)  A Yellow Frame may be converted to Green inside MEN if resources permit (rarely) • RED Traffic:  Everything exceeding EIR, traffic discarded. 74
  22. 22. Color Mode • Color Mode parameter specifies whether the UNI is operating in a color-aware or color- blind mode. • When in a color-aware mode, the prior color associated with an incoming service frame is employed. • In the color-blind mode, the prior color indication is ignored. Ingress UNI-N Egress UNI-N Color Blind Mode Color Aware Mode 75 UNI-C Ingress UNI-N Egress UNI-N UNI-C Customer’s Uncolored Frames Customer’s Colored Frames
  23. 23. Coupling Flag • CF is a Bandwidth Profile parameter. • It allows the choice between two modes of operation (value of 0 or 1) • It likely increases the number of Yellow frames (if CF=1) • Not useful in “Color Blind” mode. • Implementation operates on whole frames basis. • If Yellow token bucket fills, excess tokens are discarded. 76 CBS EBS CIR / 8 EIR / 8 CF = 1 CBS EBS CIR / 8 EIR / 8 CF = 0 CF = 1 Overflow tokens wasted These Green tokens are now considered as Yellow tokens. Discard
  24. 24. Coupling Flag • Example (Color-Aware Mode):  Assume CBS = 2000 bytes and EBS = 2600 bytes  4 consecutive frames arrived at UNI each having size 1522 bytes (1 Green followed by 3 Yellow frames)  First frame consumes 1522 bytes from CBS and marked Green  Second arrived frame is Yellow and will proceed to EBS  Now if CF=1 then;  1 Green and 1 Yellow frame confirmed.  Once CBS is full, both CIR and EIR tokens will fall in EBS.  Rest two Yellow frames may be served or only one served or both discarded (Red)  It depends upon PIR and left over EBS space.  It is very likely that at-least one Yellow frame is served out of two.  This means CF=1 can accommodate 1 Green frame and 2 Yellow frames (total 3 frames) 77
  25. 25. Coupling Flag  Third frame may be declared Red if not served by EBS and PIR (PIR=EIR+CIR)  But if CF=0 then;  1 Green and 1 Yellow frame confirmed.  Chances of 3rd frame being Yellow totally depend upon left over EBS & EIR (not PIR here so lesser chance)  4th frame may be declared Yellow or Red.  This means CF=0 has lesser chances of accommodating more than one Yellow frames (compare to CF=1). • CF has an impact on Color Aware mode only • CF value determines if the EBS can enjoy cumulative tokens of CIR and EIR. 78
  26. 26. EVC per UNI Service Attributes Service Attributes UNI Service Attributes EVC Service Attributes EVC per UNI Service Attributes Here is the list of EVC per UNI Service Attributes.  UNI EVC ID  CE-VLAN ID / EVC Map  Ingress BW Profile per EVC  Ingress BW Profile per CoS Identifier  Egress BW Profile per EVC  Egress BW Profile per CoS Identifier  The listed items may vary depending on service type in question ! 79
  27. 27. EVC per UNI Service Attributes UNI EVC ID: • A string formed by the concatenation of the UNI ID & the EVC ID. • Example: U1_EPL1 (considering U1 is UNI ID and EPL1 is EVC ID) • It is intended for management & control purposes. CE-VLAN ID / EVC Map: • It is an association of CE-VLAN IDs with EVCs at a UNI. • At each UNI there must be a mapping of each CE-VLAN ID to at most one EVC. • Constitutes a Mapping Table of CE-VLAN IDs to the EVC ID. • For Port based services, “CE-VLAN ID / EVC Map” is unnecessary. (not needed) CE-VLAN ID EVC # 16 EVC1 1000 EVC2 46 EVC3 46 1000 16 EVC3 EVC2 EVC1 UNI Untagged & Priority Tagged 80
  28. 28. EVC per UNI Service Attributes: Ingress BW Profile per EVC • A single Ingress Bandwidth Profile must be applied to all ingress Service Frames for an instance of an EVC at the UNI. • if a UNI has 3 EVCs, there could be 3 Ingress Bandwidth Profiles, one for each EVC. • The Ingress Bandwidth Profile per EVC service attribute is associated with each EVC at the UNI. • “Ingress BW Profile per EVC” & “Ingress BW Profile per CoS ID” are both “EVC per UNI” service attributes. • Egress BW Profile is optional and usually required for multipoint type EVCs. UNI EVC1 EVC2 EVC3 Ingress BW Profile Per EVC1 Ingress BW Profile Per EVC2 Ingress BW Profile Per EVC3  3 EVCs share fixed UNI BW  3 CIRs can always be met  3 EIRs can not always be assured simultaneously 81
  29. 29. Example of “Ingress BW Profile per EVC” EIR1 EIR3 CIR1 EVC1 EVC2 EVC3 UNI Example: UNI BW = 10Mbps CIR (EVC1) = 1Mbps CIR (EVC2) = 2Mbps CIR (EVC3) = 3Mbps EIR (EVC1) = 5Mbps EIR (EVC2) = 5Mbps EIR (EVC3) = 5Mbps Multiple services can be offered over a subscriber UNI and each of these services can have its own bandwidth profile. BW Profile per EVC basis UNI EVC1 EVC2 EVC3 Ingress BW Profile Per EVC1 Ingress BW Profile Per EVC2 Ingress BW Profile Per EVC3 82 CIR 1 CIR 2 CIR 3 EIR 1 EIR 2 EIR 3 UNI Rate Total CIR Excess Rate for Oversubscription
  30. 30. EVC per UNI Service Attributes: Ingress BW Profile per CoS ID UNI EVC1 CE-VLAN CoS 2 Ingress Bandwidth Profile Per CoS ID 2 CE-VLAN CoS 4 CE-VLAN CoS 6 Ingress Bandwidth Profile Per CoS ID 4 Ingress Bandwidth Profile Per CoS ID 6 EVC2 • In this, a single Ingress Bandwidth Profile must be applied to all ingress Service Frames with a specific Class of Service Identifier. • In figure below, there are three Class of Service Identifiers within EVC1, each with a separate Ingress Bandwidth Profile. • If there is a per UNI Ingress Bandwidth Profile, then there cannot be any other Ingress Bandwidth Profiles at that UNI. • If there is a per EVC Ingress Bandwidth Profile on an EVC, then there cannot be any per Class of Service Ingress Bandwidth Profiles or instances of CoS on that EVC. • Identifying Class of Service is discussed in a later slide (Day 2). 83
  31. 31. Question: BW Profile “Ingress BW Profile per UNI” can not be applied to following MEF service due to possible duplication with “Ingress BW Profile per EVC”. (select one) a) EPL b) EVPL c) EP-LAN d) EVP-Tree e) None of Above 84 Answer a) EPL

×