1. Resilience and Service Protection in EPON Hesham ElBakoury
Huawei Technologies [email protected] April 2012 IEEE
P1904.1 Seminar, Prague, Czech Republic 1
2. EPON is a Universal Access Architecture All user types
Residential Business Cellular backhaul All configurations SFU
MDU/MTU FTTH FTTC/FTTN All Data Rates 1 Gb/s (.3ah-2004) 10/1 Gb/s
(.3av-2009) 10/10 Gb/s (.3av-2009) One architecture simultaneously
supports all user types, all deployment configurations, and all
equipment generations on the same network!20 April 2012 IEEE
P1904.1 Seminar, Prague, Czech Republic 2
3. Motivation for Protection in EPON With the increasing rate
of deployments of EPON systems to support both residential and
business applications, service protection becomes of paramount
importance to maintain the QoS and high availability of these
applications A network can offer protection by providing backup
resources to be used when the primary resource fails. Survivability
is property of a network to be resilient to failure Requires
physical redundancy and protection switching mechanisms
Survivability is a very important aspect of modern networks The
ever-increasing bit rate makes an unrecovered failure a significant
loss for network operators. No network-operator is willing to
accept unprotected networks anymore.20 April 2012 IEEE P1904.1
Seminar, Prague, Czech Republic 3
4. EPON Failures The common EPON failures are: Fiber cut in
feeder/drop fiber, which affect users connected to the given fiber
trunk/branch; Failure of OLT/ONU transceivers, affecting either all
or selected users; Failure of other passive optical components,
e.g. Passive Splitter Combiner (PSC), connectors, splices etc.
Different types of OLT/ONU failures, related with all other
electronic, electric or mechanical components of these devices,
including among the others, ASIC, connectors, power supplies etc.
User (error Configuration) ODN, 19% 13% OLT(card & Transceiver)
Platform , 7% (ITMS,IPTV, SS/IMS, etc.), 26% ONU, 35%20 April 2012
IEEE P1904.1 Seminar, Prague, Czech Republic 4
5. Failure Detection in EPON Fiber Plant monitoring using OTDR
Active Monitoring Used for both fault detection and localization.
Not specified by SIEPON. Transceiver Status Monitoring SIEPON
provides network operators with ability to monitor major optical
transceiver parameters for both OLT and ONU. Link Fault Detection
BER Measurements. Failure to receive valid optical signal for more
than 2ms. Loss of single REPORT/GATE messages within 50 msec.20
April 2012 IEEE P1904.1 Seminar, Prague, Czech Republic 5
6. SIEPON Protection Techniques Two types of Optical Link
Protection are introduced by SIEPON: Trunk Protection Tree
Protection Both OLT intra-chassis and inter-chassis (dual-
homing/parenting) protection are supported. Inter-chassis
communications protocol is unspecified by SIEPON. Both on-demand
and automatic protection switching are supported. Both Line and
Client Protection are supported. Key difference depends on whether
the MAC client block uses combinatorial or sequential logic.20
April 2012 IEEE P1904.1 Seminar, Prague, Czech Republic 6
7. Line Protection In Line Protection Scheme, the entire MAC
Client data path is shared between primary and backup paths. For
example, queues and shaper/policer are shared between primary and
backup paths. Line Protection Scheme is functionally equivalent to
an implementation where a protection switch is located within an
ONU ASIC containing two line interfaces20 April 2012 IEEE P1904.1
Seminar, Prague, Czech Republic 7
8. Client Protection In Client Protection Scheme, the entire
MAC Client data path is fully decoupled. Upon protection switchover
event, the backup path starts with clean history Client Protection
Scheme is functionally equivalent to an implementation where a
protection switch connects to two separate ONU/OLT ASICs, each with
a single line interface20 April 2012 IEEE P1904.1 Seminar, Prague,
Czech Republic 8
9. Trunk Protection Trunk Protection ONU is not protected. The
OLT and trunk fiber are duplicated. Protection area Backup OLT can
be in hot or cold stand-by mode Switching time must not exceed150
msec. ONU#1 2:N optical splitter PON IF PON IF OLT 1 PON IF ONU#N
OLT 2 PON IF20 April 2012 IEEE P1904.1 Seminar, Prague, Czech
Republic 9
10. Tree ProtectionTree Protection To balance traffic loads of
different ONUs between OLT, ONU and the entire fiber plant are two
OLTs, a single OLT can act as working OLT forprotected against
failure. some ONUs, while simultaneously act as stand-by Only Hot
Stand-by mode is supported. OLT for other ONUs. Switching time must
not exceed 50 msec.20 April 2012 IEEE P1904.1 Seminar, Prague,
Czech Republic 10
11. Applications of SIEPON Protection Trunk Protection Switch
over time is