|Version 1||Breaklog 2||Language(s)||Release date||Group(s) 3|
slink2ew is a SeedLink client module for Earthworm.
The latest version is also available in the Earthworm source code repository and binaries are included in the Earthworm distribution.
The SeedLink protocol can be summarized as a simple negotiation scheme followed by the streaming of data packets from the server. SeedLink packets are composed of a small header followed by a 512-byte Mini-SEED record (data only SEED). The negotiation phase allows the client to request only specified data types from the server for each data stream. A data stream is defined by a network and station code pair.
By utilizing sequence numbers for each packet in a data stream the SeedLink protocol allows for connections to be resumed, eliminating most data gaps. The ability to resume data streams is primarily dependent on how much data, time-wise, the remote SeedLink has in it’s buffer.
The protocol allows for two different modes of data transmission, uni-station and multi-station modes. Uni-station mode operates by transmitting a single data stream (data from a single station) through one network connection. In this mode the data stream does not need to be specified by the client as it is implied by the internet address and port. Multi-station mode operates by transmitting multiplexed data streams (data from multiple stations) through a single network connection.
The maxium size of the
TRACEBUF messages created by
slink2ew is limited to the maximum number of samples (using Steim2 compression) that can fit into a 512-byte Mini-SEED record (721 samples = 2884 bytes) plus the size of the
TRACEBUF header (64 bytes). So 2948 bytes is a good estimate of the maximum size of
TRACEBUF messages created by
Version 1.1 and greater of
slink2ew supports the creation of either
TRACEBUF2 messages depending on which version of Earthworm the module was built for. By default the module will create
TRACEBUF2 messages if the system supports them and
TRACEBUF messages otherwise. Additionally there is an optional command
ForceTraceBuf1 that will force the use of
TRACEBUF messages on systems that support
More information on the IRIS DMC’s SeedLink service »
SeisComP and SeedLink are actively supported by the GEOFON Project, ORFEUS Data Center and IRIS Data Management Center in addition to the user community.
1 – Click the version release to view details about each package release including screenshots, manuals/how–to's, and revision histories. If more than one version is listed it means that a specific set of functionality was added or removed and legacy versions that preserve behaviors are archived.
2 – A list of changes that are not backwards compatible. More than one version of a package will be listed if this field has an entry.
3 – Development group(s) responsible. If IRIS and another group is listed, this usually means IRIS funded an external group for development.