| 리포트 | 기술문서 | 테크-블로그 | 글로벌 블로그 | 원샷 갤러리 | 통신 방송 통계  | 한국 ICT 기업 총람 |

제품 검색

| 네트워크/통신 뉴스 | 기술자료실 | 자유게시판 |  
 
 
섹션 5G 4G LTE C-RAN/Fronthaul Gigabit Internet IPTV/UHD IoT SDN/NFV Wi-Fi Video Streaming KT SK Telecom LG U+ OTT Network Protocol CDN YouTube Data Center
 
스폰서채널 |

 

  스폰서채널 서비스란?
Ethernet OAM Troubleshooting
July 24, 2011 | By VeEX
코멘트 (0)
6
Thank you for visiting Netmanias! Please leave your comment if you have a question or suggestion.
Transcript
Ethernet OAM Troubleshooting


. Ethernet originated as a Local Area Network (LAN) technology
. A small number of co-located stations, were all managed by a single entity so E2E performance was never a real concern
. “Carrier Class Ethernet” radically changed the situation;
. Networks need to be managed and monitored by service providers in
order to guarantee SLAs
. Ethernet MANs need to support automated defect detection and
performance measurement

. IP-based tools such as ping and trace-route are not suitable
. IP tools function at higher layers and do not relate to the underlying network or service
. Four Ethernet OAM protocols have emerged;
. IEEE 802.3ah EFM link-layer OAM
. IEEE 802.1ag Connectivity Fault Management
. MEF E-LMI Ethernet Local Management Interface
. ITU-T Y.1731 OAM Functions and Mechanisms for Ethernet networks



Ethernet Virtual Connection (EVC)



.
A flat network is difficult to manage and to define accountabilities

.
Hierarchical Maintenance Domains defines OAM Flows & OAM responsibilities


UNI UNI


.
Maintenance Association (MA)

. Boundaries of an Administrator’s scope of monitoring part of the network

.
Maintenance Domain (MD)

. A level of monitoring within the hierarchy

.
Maintenance End Points (MEP)

. End Points of the MA or MD

.
Maintenance Intermediate Points (MIP)


. Intermediate Points within MA or MD


. Discover an OAM peer, and automatically detect its capabilities
. Indicate whether the test set serves in active or passive mode.
. Specify the Vendor OUI (Organizationally Unique Identifier) for the instrument
. Indicate whether the instrument will advertise that it provides unidirectional support for failure detection, remote loopback, link events, and variable retrieval
. Indicate whether you want the instrument to generate link faults, dying gasps, and critical events.

. Specification of the Maintenance Domain (MD) level, Maintenance Entity Group (MEG) End Point IDs, and Maintenance Association (MA) IDs.
. Specify the Continuity Check Message (CCM) transmission rate
. Specify the CCM and LBM Multicast address
. Specify thresholds for clearing a loss of continuity (LOC) if the number of consecutive missing CCM exceeds the number of messages expected within the calculated interval.
. NOTE: Link OAM PDUs will be sent together with Throughput test traffic. When OAM is enabled we will have the option to send 0% test traffic, in order to only send out OAM traffic. Most of the time it will be sent out with test traffic.



.
Each layer supports OAM capabilities independently

.
OAMs interoperate with each other

.
Component responsibilities are complementary



IEEE 802.3ah Link OAM
. Link-layer OAM was developed for “Ethernet in the First Mile” (EFM) . Provides functions for network segments (access links & individual circuits) . Operates purely at the Ethernet layer, and does not require an IP address . Link-layer OAM messages are sent in untagged slow protocol frames called
OAM Protocol Data Units, or OAMPDUs.

. Slow protocols are restricted in the number of protocol frames transmitted per second (for OAMPDUs . no more than 10 frames per second)
. Uses Ethertype 88-09 and is differentiated by a sub-type of 03 that appears as the first byte of the MAC client payload.
. OAMPDUs contain control and status information to monitor, test and
troubleshoot OAM-enabled links.

. Provides Link Fault Detection, Monitoring and Loopback functionalities
. Monitors individual links only, not end-to-end EVC


Defined by the flag and code fields;
. Information code

. OAMPDUs are used for auto-discovery, heartbeat, and fault notification
. Event notification OAM frames

. report various link statistics e.g. symbol errors and total frames with errors since the OAM sub-layer was reset
. Variable request and variable response frames

. Service provider MIB variable requests to obtain customer configuration
. Loopback control OAM frames

. used to enable or disable intrusive loopback in a remote passive-mode device
. Organization specific frames


. Discovery . Link Performance Monitoring . Remote Loopback . Fault Detection . Collecting Performance Statistics . Organizational Specific Extensions





. Discovery
. First phase of 802.3ah OAM protocol which identifies the 802.3ah capable link partner . Necessary for link partners to communicate their OAM capabilities and configurations because 802.3ah is a multi-vendor, non-proprietary protocol

. Link performance monitoring
. Detection and notification of link performance (quality) faults . Uses the Event Notification OAM Protocol Data Units (OAMPDUs) which are sent to OAM capable devices when error traffic is detected . Ethernet data performance can deteriorate slowly before disrupting service, so the 802.3ah standard enables a user to set the level of threshold that generates an event OAMPDU


. Remote Loopback
. An 802.3ah OAM-capable device can put its remote link partner into loopback mode using a loopback control OAMPDU . Every frame received is transmitted back on the same port to ensure the quality of links during installation or troubleshooting

. Fault Detection
. An OAMPDU flag allows an 802.3ah-capable device to convey severe events to its OAM link partner. 802.3ah OAM Detects and indicates the following conditions:
. Link Fault: Loss of link is detected by receiver . Dying Gasp: Unrecoverable condition such as power failure is sent to
the remote link partner . Critical Event: Organization specific critical event or major failure . Unidirectional Fault Detection

. Link OAM -Per link (point-to-point): . Link monitoring --Remote loopback . Remote failure indication --Loopback Control

. Good for single links, but it does not monitor across EVC !
UNIUNI

802.3ah
802.3ah
802.3ah
802.3ah
802.3ah
802.3ah
802.3ah
802.3ah
802.3ah



IEEE 802.1ag -“Connectivity Fault Management” across EVC

. Continuity Check Messages (CCM)
. Loopback Message (LBM)
. Link trace Message (LTM)

ITU-T Y.1731 . “OAM Functions & Mechanisms for Ethernet networks”
. Provides all of the 802.1ag functionality with additional performance monitoring capabilities including: . Frame Loss LM), Delay (DM) and Delay Variation Measurements . Automatic Protection Switching



Continuity Check Messages (CCM)
.MEPs periodically exchange Continuity Check OAMmessages to detect loss of continuity or incorrectnetwork connections.
.Multicast to each MEP in a MA/MEG at each
administrative level.

.Can be used to perform two way dual-ended Frame Loss measurements.
.Incorporates a Flag field which includes a bit forRemote Defect Indication (RDI) and an indication ofthe period at which CC Messages are transmitted.

Loopback Message (LBM)
. MEPs send loopback messages to verify connectivity with another MEP or MIP for a specific MA/MEG.
. Acts like a ping type request/reply function. A MEP sends a loopback request message to another MEP or MIP, which generates a subsequent LRM.
. LBMs / LRMs are used to verify bidirectional connectivity. They are typically initiated by operator command.
. A MEP can be provisioned to send LBMs periodically.
. For IEEE 802.1ag, loopback is a unicast OAM message.

. Loopback can also be used as an out of service diagnostic test. (applies to unicast loopback frames only)



Link Trace Message (LTM)
.MEPs multicast LTMs on a particular MA/MEG to identify adjacency relationships with remote MEPsand MIPs at the same administrative level.
.LTM can also be used for fault isolation. .The message body includes a destination MACaddress of a target MEP that terminates the linktrace. .When a MIP or MEP receives an LTM, it generates a unicast LTR to the initiating MEP. .It also forwards the LTM to the target MEPdestination MAC address. .An LTM effectively traces the path to the target MEP.

. AIS: Alarm Indication Signal, will initiate the transmission of AIS in the presence of certain defect conditions and will take the appropriate actions on its reception.
. RDI: Remote Defect Indication, it is used both for fault management and performance monitoring. RDI is transmitted on the detection of a defect and cleared when the defect clears by a MEP.
. APS: Automatic Protection Switching
. Ethernet Locked Signal: used to indicate that data traffic is intentionally being interrupted for administrative purposes like testing. It help to differentiate between a defect condition and controlled suspension of traffic.


.Performance Management: single and dual ended measurements
.Frame Loss
.Delay
.Delay Variation
.Throughput




Thank You

Any Questions?

Confidential & Proprietary Information of VeEX Inc.
View All (815)
4G (2) 4G Evolution (1) 5G (35) 5g (1) 802.11 (1) 802.1X (1) ALTO (1) ANDSF (1) AT&T (2) Acceleration (1) Adobe HDS (3) Akamai (6) Amazon (3) Apple HLS (4) Authentication (1) BRAS (2) BT (1) Backbone (4) Backhaul (12) BitTorrent (1) Broadcasting (3) C-RAN (13) C-RAN/Fronthaul (12) CCN (4) CDN (52) CDNi (1) COLT (1) CORD (1) CPRI (2) Cache Control (1) Caching (5) Carrier Cloud (2) Carrier Ethernet (9) Channel Zapping (4) China Mobile (1) China Telecom (1) Cloud (10) Cloudfront (1) DASH (2) DCA (1) DHCP (3) DNS (1) DSA (1) Data Center (7) Dynamic Web Acceleration (1) EPC (5) Energy (1) Ericsson (5) Ethernet (8) FEO (2) Fairness (1) Fronthaul (5) GiGAtopia (1) Gigabit Internet (2) Global CDN (1) Google (5) HLS (1) HTTP (1) HTTP Adaptive Streaming (18) HTTP Progressive Download (3) HTTP Streaming (1) HetNet (1) Hot-Lining (1) Hotspot 2.0 (2) Huawei (3) ICN (4) IP (1) IP Allocation (1) IP Routing (8) IPTV (15) Intel (1) Internet (1) Interoperability (2) IoST (1) IoT (14) KT (22) LG U+ (3) LTE (70) LTE MAC (1) LTE-A (2) Licensed CDN (1) M2M (3) MEC (2) MPLS (25) MVNO (1) Market (4) Metro Ethernet (7) Microsoft (2) Migration (1) Mobile (4) Mobile Backhaul (1) Mobile Broadcasting (1) Mobile CDN (2) Mobile IP (1) Mobile IPTV (3) Mobile Video (1) Mobile Web Perormance (1) Mobility (1) Multi-Screen (7) Multicast (7) NFC (1) NFV (2) NTT Docomo (2) Netflix (6) Network Protocol (31) Network Recovery (3) OAM (6) OTT (31) Ofcom (1) Offloading (2) OpenFlow (1) Operator CDN (14) Orange (1) P2P (4) PCC (1) Page Speed (1) Programmable (1) Protocol (7) Pseudowire (1) QoS (5) Router (1) SCAN (1) SD-WAN (1) SDN (15) SDN/NFV (15) SK Telecom (21) SON (1) SaMOG (1) Samsung (2) Security (6) Service Overlay (1) Silverlight (4) Small Cell (3) Smart Cell (1) Smart Grid (2) Smart Network (2) Supper Cell (1) Telefonica (1) Telstra (1) Terms (1) Traffic (2) Traffic Engineering (1) Transcoding (3) Transparent Cache (2) Transparent Caching (14) VLAN (2) VPLS (2) VPN (9) VRF (2) Vendor Product (2) Verizon (2) Video Optimization (4) Video Pacing (1) Video Streaming (14) Virtual Private Cloud (1) Virtualization (3) White Box (1) Wholesale CDN (4) Wi-Fi (13) WiBro(WiMAX) (4) Wireless Operator (5) YouTube (4) eMBMS (4) eNB (1) 망이용대가 (1) 망중립성 (1) 스마트 노드 (1)

 

 

     
         
     

 

     
     

넷매니아즈 회원 가입 하기

2019년 1월 현재 넷매니아즈 회원은 49,000+분입니다.

 

넷매니아즈 회원 가입을 하시면,

► 넷매니아즈 신규 컨텐츠 발행 소식 등의 정보를

   이메일 뉴스레터로 발송해드립니다.

► 넷매니아즈의 모든 컨텐츠를 pdf 파일로 다운로드

   받으실 수 있습니다. 

     
     

 

     
         
     

 

 

비밀번호 확인
코멘트 작성시 등록하신 비밀번호를 입력하여주세요.
비밀번호