This chapter describes the level of support that Cisco ANA provides for time-division multiplexing (TDM), Digital Signal (DSx) Hierarchy, and related physical technologies, as follows:
Time-Division Multiplexing (TDM) is a type of digital multiplexing in which two or more signals or bit streams are transferred apparently as subchannels in one communication channel. The transmission of these streams appears to be simultaneous, but they are actually taking turns on the channel. This is done by dividing the transmission time domain into several recurrent slots of fixed length, one for each subchannel. A sample byte or data block of subchannel 1 is transmitted during timeslot 1, subchannel 2 during timeslot 2, and so on. One TDM frame consists of one timeslot per subchannel. After the last subchannel, the cycle starts again with a new frame, starting with the second sample, byte or data block from subchannel 1, and so on.
DSx
Digital Signal (DSx) Hierarchy refers to the rate and format of digital telecommunication circuits, as part of the North American Digital Hierarchy. DSx is related to the T-carrier designations. However, DS refers to multiplexing techniques, while the T designations refer to the underlying equipment and signaling. There are various DS levels, the most common being:
•DS0/Fractional T1 (64 Kb/s), which represents a single voice telephone call.
•DS1/T1 (1.544 Mb/s), with 24 user channels.
•DS2/T2 (6.312 Mb/s), with 96 user channels.
•DS3/T3 (44.736 Mb/s), with 672 user channels.
T3/E3
T-carrier telecommunications is a generic name for several digitally multiplexed telecommunications carrier systems used in North America, Japan, and Korea. The basic unit of the T-carrier system is the Fractional T1, which corresponds to the Digital Signal Hierarchy's DS0, and is commonly used for one voice circuit.
The E-carrier system (the "E" stands for "European") is incompatible with the T-carrier system (though cross-compliant cards exist). It is in common use everywhere outside of North America, Japan, and Korea. It typically uses the E1 (2.048 Mb/s) and E (334.368 Mb/s) line rates.
Channelized T3, OC3, DS3 Interface
Channelization, coupled with native edge-aggregation services such as MPLS and QoS, allows service providers and large enterprises to save dramatically on power, floor space, local-loop charges, and equipment costs, by permitting receipt and transmission of multiplexed T3, OC3 and DS 3 circuits over high-bandwidth physical media.
Circuit Emulation over MPLS
In CEM, TDM bitstream connections (T1, E1, T3, E3) are encapsulated as pseudowires over the MPLS backbone. Both structured and structure-agnostic TDM bitstreams are supported.
1588 Clocking
TDM 1588 is known as Precision Time Protocol (PTP). The PTP standard specifies a clock synchronization protocol applicable to distributed systems consisting of one or more nodes communicating over a network. Nodes are modeled as containing a real-time clock that may be used by applications within the node for various purposes, such as generating time stamps for data or ordering events managed by the node. The protocol provides a mechanism for synchronizing the clocks of participating nodes to a high degree of accuracy and precision.
SyncE Clocking
One of the fundamental requirements placed on next-generation networks is to provide the ability to distribute precision frequency or timing synchronization around the network. Frequency synchronization is provided by SONET/SDH equipment. used in conjunction with external timing technology, such as Cesium oscillators and GPS.
As SONET/SDH equipment is replaced by Ethernet equipment, this frequency synchronization ability is required over Ethernet ports. Synchronous Ethernet (SyncE) provides SONET/SDH physical layer (POS-PHY) frequency distribution of known, common precision frequency references.
To maintain SyncE links, a set of operations messages is required. These messages provide information about the quality of the timing source being used to clock the SyncE link, ensuring that each node is always deriving timing from the most reliable source. In SONET/SDH networks, these messages are known as Synchronization Status Messages (SSM). Each timing source has a Quality Level (QL) associated with it, which gives the accuracy of the clock. This QL information is transmitted across the network via SSMs over the Ethernet Synchronization Messaging Channel (ESMC), or via SSMs contained in the SONET/SDH frames, so that devices can know the best available source with which to synchronize. To define a preferred network synchronization flow and help prevent timing loops, users can assign priority values to particular timing sources on each router. The combination of QL information and user-assigned priority levels allows each router to choose a timing source to clock its SyncE and SONET/SDH interfaces.
Note Cisco ANA supports these technologies only in conjunction with data link layer technologies, such as ATM or PoS.
The data link layerDS0 Bundle Interface object is bound by its Containing Termination Points attribute to either DS1 Physicalor DS3 Physical Layer objects. It is accessed primarily by the data link layer object, such as the ATM Interface and the Frame Relay Interface, bound by its Contained Connection Termination Points attribute.
Table 29-1 DS0 Bundle Interface (IDS0Bundle)
Attribute Name
Attribute Description
Scheme
Polling Interval
Bundled Time Slots
Bundled time slots (DS1 channels).
Product
Configuration
Bundle Location
Bundle location/index.
Product
Configuration
AdminStatus
The administrative status of the interface (Down, Testing, Up).
IPCore
Configuration
OperStatus
The operational status of the interface (Down, Testing, Up).
IPCore
Configuration
IANA Type
Internet Assigned Numbers Authority (IANA) type of the sublayer.
N/A
N/A
Containing Termination Points
Underlying termination points (connection or physical).
The CEM Interface object represents a CEM-encapsulated E1/T1 circuit interface.
Table 29-4 CEM Interface (ICEMEncap)
Attribute Name
Attribute Description
Scheme
Polling Interval
cemIfName
The interface name (for example, CEM8/0/0 or Virtual-cem8/0/24).
IPCore
Configuration
CEM Group
The CEM Group object represents a CEM Group configured on a physical or virtual CEM Interface.
Table 29-5 CEM Group (ICEMGroup)
Attribute Name
Attribute Description
Scheme
Polling Interval
ID
The DS0 bundle CEM group identifier.
IPCore
Configuration
IdlePattern
The 8-bit hexadecimal number that is transmitted on a T1 or E1 line when missing packets are detected on the PW circuit.
IPCore
Configuration
IdleCAS
When channel associated signaling (CAS) is used, the 8-bit hexadecimal signal that is sent when the CEM interface is identified as idle.
IPCore
Configuration
DeJitter
The size of the dejitter buffer in milliseconds (ms) (in the range 4-500, 4 is the default).
IPCore
Configuration
PayloadSize
The size of the payload (in bytes) for packets on the CEM interface (in the range 32-1312).
IPCore
Configuration
RTP
Indicates whether RTP compression is enabled or disabled.
IPCore
Configuration
RTPHeader
Indicates whether RTP header compression is enabled or disabled.
IPCore
Configuration
TimeSlots
The range of timeslots (DS0 channels) allotted to the CEM interface. Empty if the Structure-Agnostic TDM over Packet (SAToP) method is used.
IPCore
Configuration
Pseudowire
The name of the pseudowire configured on the CEM interface.
IPCore
Configuration
AdminStatus
The administrative status of the CEM interface (Down, Testing, Unknown, Up).
IPCore
Configuration
OperStatus
The operational status of the CEM interface (Dormant, Down, Not Present, Testing, Unknown, Up).
IPCore
Configuration
Clock Service
The Clock Service object models the generic clocking configuration and clocking features of a network element, independent of any particular timing scheme, such as PTP or Anonymous Call Rejection (ACR).
Table 29-6 Clock Service (IClockService)
Attribute Name
Attribute Description
Scheme
Polling Interval
ActiveClockSource
The current active clock source used by the network element.
Any
Configuration
NcsMode
The network clock selection mode (revert, nonrevert, unknown). NCS is used in case of master device failure.
Any
Configuration
HoldTimeout
The network clock selection hold timeout in seconds (in the range 0-86400, -1 for no timeout).
Any
Configuration
UseStratum4
Indicates whether the Stratum4 clock is used (true) or not (false). The default is false, which means the Stratum3 clock is used.
Any
Configuration
Mode
The network element clocking mode (unknown, slave, master, hybrid).
Indicates the currently selected Ethernet Equipment Clock option (EEC-Option I, EEC-Option II).
Any
Configuration
clockMode
Indicates whether Quality Level is enabled (QL-Disable, QL-Enable).
Any
Configuration
ssmOption
Indicates which of the Synchronization Status Messages (SSM) options is currently in use on the NE (ITU-T Option I, ITU-T Option II generation 1, ITU-T Option II generation 2).
Any
Configuration
esmcMode
Indicates whether Ethernet Synchronization Messaging Channel is enabled on the NE (true) or not (false).
Any
Configuration
holdOffTimer
The amount of time (in milliseconds) the NE waits before removing a source that has gone down (values in the range 0 to 50000, default is 300).
Any
Configuration
waitToRestore
The amount of time (in milliseconds) the NE waits before adding a source that has just come up (values in the range 0 to 86400).
Any
Configuration
Revertive
Indicates whether Revertive mode is enabled (true) or disabled (false) on the NE.
Any
Configuration
SyncE Interface
The SyncE Interface object represents the Synchronous Ethernet configuation for a single interface on an NE.
Table 29-13 SyncE Interface (ISyncEInterface)
Attribute Name
Attribute Description
Scheme
Polling Interval
selectionInput
Assign the interface as a timing source to be passed to the selection algorithm.
Any
Configuration
ingressESMCMode
Indicates whether Ethernet Synchronization Messaging Channel is enabled (true) or disabled (false) for incoming QL information on the interface.
Any
Configuration
egressESMCMode
Indicates whether Ethernet Synchronization Messaging Channel is enabled (true) or disabled (false) for outgoing QL information on the interface.
Any
Configuration
ingressQLMode
Indicates whether incoming quality level information is enabled (true) or disabled (false) on the interface.
Any
Configuration
ingressQuality
Indicates the type of incoming quality level information, depending on the globally configured SSM option. For ITU-T Option I, available values are QL-PRC, QL-SSU-A, QL-SSU-B, QL-SEC, and QL-DNU. For ITU-T Option II generation 1, available values are QL-PRS, QL-STU, QL-ST2, QL-SMC, QL-ST4, QL-DUS. For ITU-T Option II generation 2, available values are QL-PRS, QL-STU, QL-ST2, QL-TNC, QL-ST3, QL-SMC, QL-ST4, QL-DUS.
Any
Configuration
egressQLMode
Indicates whether incoming quality level information is enabled (true) or disabled (false) on the interface.
Any
Configuration
egressQuality
Indicates the type of outgoing quality level information, depending on the globally configured SSM option. For ITU-T Option I, available values are QL-PRC, QL-SSU-A, QL-SSU-B, QL-SEC, and QL-DNU. For ITU-T Option II generation 1, available values are QL-PRS, QL-STU, QL-ST2, QL-SMC, QL-ST4, QL-DUS. For ITU-T Option II generation 2, available values are QL-PRS, QL-STU, QL-ST2, QL-TNC, QL-ST3, QL-SMC, QL-ST4, QL-DUS.
Any
Configuration
waitToRestore
The amount of time (in milliseconds) the interface waits before adding a source that has just come up (values in the range 0 to 86400).
Any
Configuration
holdOffTimer
The amount of time (in milliseconds) the interface waits before removing a source that has gone down (values in the range 0 to 50000, default is 300).
Any
Configuration
Vendor-Specific Inventory and IMOs
There are no vendor-specific inventory or IMOs for this technology.
Network Topology
Cisco ANA does not support discovery of physical layer topology. This topology is manually (statically) configured by the system administrator. However, it is used in conjunction with the data link layer above it, such as ATM, for discovering its physical topology, while further verifying it by matching the traffic signature of these ports using Cisco's confidential scheme, which requires a substantial amount of traffic in order to function correctly.
Service Alarms
The following alarms are supported for this technology: