iLink Architecture
For iLink order entry on the CME Globex platform, CME provides two gateway access models. Â
Convenience Gateway (CGW) - provides a connection to any CGW session, which manages routing for all order entry messages to all market segments;Â routing is transparent to customer.
Market Segment Gateway (MSGW) - provides a connection to a dedicated market segment, which is defined as a group of products on a given trading engine instance.
Connecting directly to MSGWs involves a separate Session ID model, messaging behavior, and functional differences from that of the CGW.
Customers can choose to access CME Globex markets through the MSGWs or CGWs, which route through the MSGWs.
Contents
iLink Architecture Video Overview
Watch this brief video for an overview of iLink architecture.
iLink Session Model
For CGW, Session ID can exist on only one CGW.
For MSGW, Session IDs are shared across multiple MSGWs. Customers utilize a single Session ID, password, and port across all MSGWs.
Customers use their given Session ID, password, and port to connect to different MSGWs by their IP address.
Each iLink MSGW has a unique IP address for each of the primary and backup MSGWs.
Customers must manage the relationship between iLink sessions and corresponding IP addresses and market segments within their order management systems.
The diagram below shows how Session IDs are shared across multiple MSGWs.
Sequence streams are unique per Market Segment ID and Session ID combination. For example, if session ABC has logged into Market Segment ID 50 and 60, then session ABC could receive Execution Reports from both market segments with the same message sequence number (tag 34-MsgSeqNum).
iLink Fault Tolerance
For iLink, Fault Tolerance is managed at the gateway application level. iLink has a designated host that is primary and another that is designated backup.
Customers must successfully log on to the primary before attempting to log on to the backup.
If a session logs on to the backup gateway before logging on to the primary gateway, CME Globex will send a Logout message (tag 35-MsgType=5), with tag 58-Text =Â Invalid Logon. Must be logged on to Primary. Logout forced.
Customers can only trade through primary connections.
Customers can connect to the backup, but can send only Administrative messages (e.g. Test Request, Heartbeat). Application messages sent to a backup gateway are rejected.
Disconnecting or logging out from the primary gateway—either client- or exchange-initiated—will trigger an automatic logout or disconnect from the backup gateway as well, except in the Primary gateway failure scenario.
A Logout message (tag 35-MsgType=5) with tag 58-Text = Logout initiated due to disconnect on primary connection will be sent from CME Globex to the customer.
If the primary gateway fails, failover occurs by promoting the backup gateway to assume the primary role.
During the designated primary instance failure condition, CME Group may keep the designated backup instance as primary gateway.Â
Customers who experience log on issues with their primary iLink sessions must rely on the reason text (tag 58) to detect if they are connecting to primary gateway, which could be different than the primary host IP address.
To re-establish connection successfully, customer must log on to their backup iLink sessions.
iLink Fault Tolerance Scenarios
Scenarios | Given Primary Gateway State | Given Backup Gateway State | When | Then Primary Connection State | Then Backup Connection State | Result |
---|---|---|---|---|---|---|
Initial Logon to Primary Session | Not connected | Not connected | Logon to primary followed by Logon to backup | Logged on | Logged on | Client system uses the fault tolerance feature. Client system must send a Logon message to primary gateway first with the Fault Tolerance Indicator (FTI) in tag 49-SenderCompID set to 'U' for undefined. |
Initial Logon to Primary Session | Not connected | Not connected | Logon to backup |  | Logged out | New behavior Client system sends a Logon to backup gateway first. CME Globex sends a Logout (tag 35-MsgType=5) message. |
Primary Session Disconnect | Logged on  | Logged on | Disconnect from primary | Disconnected | Logged out | Client system is disconnected from primary gateway, the backup connection is logged out as well. All resting orders are cancelled for all Cancel on Disconnect registered iLink sessions. All resting quotes are cancelled on behalf of the iLink 2 Mass Quote customers. |
Backup Session Disconnect | Logged on | Logged on | Disconnect from backup | Logged on | Disconnected | A TCP disconnection from backup gateway does not affect primary connection. Resting orders and quotes are not cancelled. |
Logout from Primary Session | Logged on | Logged on | Logout from primary | Logged out | Logged out | Client system is logged out from primary gateway, the backup connection is logged out as well. If the logout is exchange initiated, all resting orders are cancelled for all Cancel on Disconnect registered gateway sessions. All resting quotes are cancelled on behalf of the Mass Quote customers. |
Logout from Backup Session | Logged on | Logged on | Logout from backup | Logged on | Logged out | Logout from backup gateway does not affect primary connection. All resting orders and quotes are not cancelled. |
Logon with Fault Tolerance (FTI value of U, P, or B) | Logged on | Logged on | Primary MSGW Failure | Disconnected | Backup connection becomes Primary | Newly promoted primary will send a heartbeat. Resting orders are not cancelled. All resting quotes are cancelled on behalf of Mass Quote customers. |
Logon with Fault Tolerance (FTI value of U, P, or B) | Logged on | Not connected | Primary MSGW Failure | Disconnected | Session must connect and login to the new promoted primary. | All resting orders are cancelled for all Cancel on Disconnect registered iLink sessions. All resting quotes are cancelled on behalf of Mass Quote customers. |
Logon without Fault Tolerance (FTI value of N) | Logged on | Not allowed to connect | Primary MSGW Failure | Disconnected | Session must connect and login to the new promoted primary. | All resting orders are cancelled for all Cancel on Disconnect registered iLink sessions. All resting quotes are cancelled on behalf of Mass Quote customers. |
Logon with Fault Tolerance (FTI value of U, P, or B) | Logged on | Logged on | Backup MSGW Failure | Logged on | Session must connect and login to the restored backup. | The failed backup is restored. All resting orders and quotes are not cancelled. |
Logon without Fault Tolerance (FTI value of N) | Logged on | Not allowed to connect | Backup MSGW Failure | Logged on | Not connected | The status of the primary connection remains intact. All resting orders and quotes are not cancelled. |
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Convenience Gateway
Customers can continue access and trade on the "standard" iLink gateway, referred to as the iLink Convenience Gateway (CGW).
The CGW allows the client system to connect to any CGW session, which manages routing for all order messages.
CGW FIFO Message Processing Model
The CGW FIFO message handling is enforced once the message reaches the MSGW. The following diagram shows the CGW model in which the example Session, AB1, exists on a single gateway.
CGW Sequence Number Management
CGW message sequencing is managed using the SenderCompID value as in standard iLink Session Layer - Message Sequence Numbers.
Market Segment Gateway
One iLink MSGW provides connectivity to a single market segment. Currently there are 17 market segments or groups of products on a given trading engine instance.
SFTP - MSGW Configuration
An SFTP site (sftpng.cmegroup.com), accessed via a CME Globex network direct connection, is used to disseminate the MSGW configuration information. The MSGW Configuration allows client systems to receive the list of all market segments and MSGW IPs. This SFTP site contains the configuration files for all environments. The SFTP site is a secure site that requires a user name and password for access.
Table Key:
Environment - specific environment (i.e., Certification, New Release, Production).
  Note: The Autocert+ tool will use the NR MSGW config file.
Service - the Configuration service.
SFTP Site - address of SFTP site.
User Name - identifies the user name.
Password - identifies the password.
Directory Location - identifies the directory.
Client System Update Schedule - Client systems should download updates according to the schedule specified.
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Environments | Service | SFTP Site | User Name | Password | Directory | Client System Update Schedule |
---|---|---|---|---|---|---|
Production | Configuration | sftpng.cmegroup.com | cmeconfig | G3t(0nnect3d  | /MSGW/Production/Configuration  | daily  |
Certification | /MSGW/Cert/Configuration  | daily | ||||
New Release Certification | /MSGW/NRCert/Configuration | daily |
MSGW FIFO Message Processing
The MSGW ensures messages are processed in the order in which they arrive at the gateway.
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MSGW Sequence Number Management
A single session is able to login to all 17 MSGW instances. To manage message sequence numbers, the customer must leverage the combination of Session ID (the first 3 characters of tag 49-SenderCompID) and tag 1300-MarketSegmentID.Â
CME Globex is currently comprised of 17 market segments. The number of market segments and the instruments listed on each can change in the future. Customers are strongly encouraged to rely programmatically on tag 1300-MarketSegmentID in the Market Data Security Definition message to route orders to the correct MSGW.
 | CGW Session ID | MSGW Session ID |
---|---|---|
Number of TCP connection(s) | 1 TCP connection to access all market segments | 1 to 17 TCP connections to access all market segments |
Number of sequence stream(s) | 1 sequence stream | Customers must manage 1 to 17 different sequence streams based on the combination of Session ID and Market Segment ID |
Tag 57-TargetSubID
Customers may connect directly to all Market Segment Gateways using the same Session ID. Customers can use tag 1300-MarketSegmentID from the market data Security Definition (tag 35-MsgType=d) message to specify the market segment for the products they want to trade on CME Globex.
For iLink messages sent from the client system to CME Globex, MSGW customers can leverage tag 57-TargetSubID to specify the market segment of the instrument. Tag 57-TargetSubID contains the tag 1300-Market SegmentID value. CME Globex will respond and echo back tag 57-TargetSubID values submitted in the customer iLink message on tag 50-SenderSubID.
Example
Time | From Client System to CME Globex | From CME Globex to Client System | Tag 35-MsdType | Tag 49-SenderCompID | Tag 50-SenderSubID | Tag 57-TargetSubID |
---|---|---|---|---|---|---|
1 | Logon | Â | A | ZUB007N | ATS | 74 |
2 | Â | Logon Ack | A | CME | 74 | ATS |
3 | Â | Test Request | 1 | CME | 74 | ATS |
4 | New Order | Â | D | ZUB007N | ATS | 74 |
5 | Â | Execution Report | 8 | CME | 74 | ATS |
6 | Logon | Â | A | ZUB007N | ATS | 68 |
7 | Â | Logon Ack | A | CME | 68 | ATS |
8 | Â | Test Request | 1 | CME | 68 | ATS |
9 | New Order | Â | D | ZUB007N | ATS | 68 |
10 | Â | Execution Report | 8 | CME | 68 | ATS |
MSGW will reject any attempts to logon with an incorrect Market Segment ID with a Logout message (tag 35=5) including tag 58 =Â Invalid TargetSubID(tag 57).
MSGW will reject any application message with an instrument not assigned to that particular Market Segment ID with a Session Level Reject(tag 35=3) including tag 58 =Â Invalid SecurityDesc(tag 107).
MSGW Failover Scenarios
During a MSGW failover from the primary to the backup instance, customer iLink messages will be rejected.
During the primary MSGW failover to backup:
CME Globex initiates failover to backup MSGW.
CGWs will reject all incoming business messages for instruments on the impacted Market Segment with a Session Level Reject (tag 35=3) with tag 58=Technical Error – Market Segment: <MarketSegmentID> is not available at this time.
If the MSGW failing over is for a futures engine, all of the options on the associated options engine will automatically transition to a trading halt (MDP Security Status(tag 35-MsgType=f) message with tag 326-SecurityTradingStatus=2 and tag 327-HaltReason=0). This trading halt applies to all of the options on the market segment. All resting mass quotes are cancelled during the transition. During the halt, customers can submit, modify and cancel orders. Mass quotes are rejected. This halt is maintained for a few seconds after the futures MSGW has resumed trading.
Technical Pause is introduced, which allows customers to cancel existing orders and to ensure that all messages sent during the MSGW failover are acknowledged by CME Globex.
Technical Pause is indicated by MDP Security Status (tag 35-MsgType=f) message  with:
tag 326-SecurityTradingStatus=2 (Trading Halt) and tag 327-HaltReason=6 (Recovery in process)
During the Technical Pause only order cancellation is allowed.
There are 2 scenarios where technical pause will be initiated:
The current market state is in a less restrictive state than Pause (i.e. Open, Pre Open)
The current market state is already in Pause
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After the Technical Pause:
MSGW will replay customer iLink messages that were not processed during the failover
CME Globex will reject those replayed messages, except Cancel messages.
Technical Pre Open - Technical Pre Open will follow the technical pause to allow adequate time for order entry and price discovery before reopening the markets.
Technical Pre Open MDP Security Status(tag 35-MsgType=f) message is generated with:
MDP 3.0: tag 326-SecurityTradingStatus=21 (Pre Open) and tag 327-HaltReason=6 (Recovery in process).
tag 326-SecurityTradingStatus=21 (Pre Open)
During the Technical Pre Open state, Order Entry is allowed, except for FAK, FOK, and Market order types.
Similar to the Technical Pause, if the current market state is more restrictive than Pre Open, Pre Open will not be initiated.
After the market is re-opened, order entry will be allowed.
The following diagram illustrates the process above.
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Backup MSGW Failure
If the backup MSGW fails:
The failure of a backup component will not affect the primary connection state.
The failed backup MSGW is restored.
CME Globex Timestamps
 Watch this brief video for an overview of CME Globex timestamps.
The diagram shows all timestamps for iLink and MDP 3.0 messages:
All MDP 3.0 timestamps are in nanoseconds with microsecond precision.
The iLink timestamp (tag 5979-RequestTime) is in nanoseconds with microsecond accuracy.
Timestamp(1) on iLink and MDP 3.0 represents the time when the order reaches the Market Segment Gateway.
Timestamp(1) is included in the MDP 3.0 Trade Summary and Order Book Update messages.
A customer can compare timestamps with an aggressor’s timestamp to determine how much later the customer's order was submitted.
Nanosecond Timestamp (tag 5979-RequestTime)
To provide more transparency between iLink order entry and MDP 3.0 market data, iLink supports a FIX tag 5979-RequestTime on all Convenience Gateway (CGW) and Market Segment Gateway (MSGW) sessions.
This timestamp represents the time the customer iLink message was received by the Market Segment Gateway and had FIFO order handling applied. The tag provides the date and time, in Universal Time Coordinated (UTC), represented in nanoseconds past the UNIX epoch time (00:00:00 UTC on 1 January 1970). UTC Timestamps are sent in number of nanoseconds since Unix epoch synced to a master clock to microsecond accuracy.
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Tag | Name | Req | Type | Max Length | Description |
---|---|---|---|---|---|
5979 | RequestTime | N | Int | 20 | Information carried on a response to convey the time (UTC) the outbound message was processed by the MSGW application. UTC Timestamps are sent in number of nanoseconds since Unix epoch synced to a master clock to microsecond accuracy. |
Tag 5979-RequestTime will be added to the following iLink application messages sent from CME Globex to the client system:
Execution Report: Order Creation, Cancel, or Modify (tag 35-MsgType=8, tag 39-OrdStatus=0, 4 or 5)
Execution Report: Fill Notice (tag 35-MsgType=8, tag 39-OrdStatus=1 or 2)
Execution Report: Trade Cancel (tag 35-MsgType=8, tag 39-OrdStatus=H)Â
Execution Report: Order Elimination (tag 35-MsgType=8, tag 39-OrdStatus=4 or C
Execution Report Order Status Request Acknowledgment (tag 35-MsgType=8, tag 150-ExecType=I)
Execution Report: Reject (tag 35-MsgType=8, tag 39-OrdStatus=8)
Order Cancel/Replace Reject (tag 35-MsgType=9, tag 434-CancelRejResponseTo=2)
Order Cancel Reject (tag 35-MsgType=9, tag 434-CancelRejResponseTo=1)
Order Mass Action Report (tag 35-MsgType =Â BZ)
Quote Acknowledgment (tag 35-MsgType=b)
Quote Reject (tag 35-MsgType=b, tag 297-QuoteAckStatus =5)
Quote Cancel Acknowledgment (tag 35-MsgType=b, tag 297-QuoteAckStatus=1, 3, 4 or 5 without tag 9775-UnsolicitedCancelType)
Only for Solicited Quote Cancel
All Administrative messages and the following Application messages sent from CME Globex to the client system will not include this new tag:
Quote Cancel Acknowledgment (tag 35-MsgType=b, Tag 9775--UnsolicitedCancelType=A, B, C, D, E, F or H)
Only for Unsolicited Quote Cancel
iLink Unsolicited Outbound Message Scenario
For unsolicited outbound messages where there are no iLink inbound messages, tag 5979 will represent the time at which the transaction is processed on the trading engine in nanoseconds.
Scenario | Tag 5979 | Tag 60 |
---|---|---|
Fill Execution Reports (35=8, 39=1,2) | The time at which the aggressing order reached the MSGW in nanoseconds. If no aggressor (e.g., Pre-open), will contain the engine event time in nanoseconds. | The time at which the aggressing order reached the MSGW in milliseconds If no aggressor (e.g., pre-open), contains the engine event time in milliseconds. |
Stop Order Trigger Ack (35=8, 39=0, 40=2) | The time at which the original aggressing order, which initiated the fill event that triggered the stop order, reached the MSGW in nanoseconds. If no aggressor (e.g., Pre-open) is present, will contain the engine event time in nanoseconds. | The time at which the original aggressing order, which initiated the fill event that triggered the stop order, reached the MSGW in milliseconds. If no aggressor (e.g., Pre-open) is present, will contain the engine event time in milliseconds. |
FAK Elimination Acks (35=8, 39=C) | The time at which the corresponding order reached the MSGW in nanosecond | The time at which the corresponding order reached the MSGW in millisecond |
Trade Bust Execution Report (35=8, 39=H) | The time of trade bust event in nanoseconds. | The time of the trade bust event in milliseconds. |
Unsolicited Mass Quote Cancel Ack (35=b, 9775=A,B,C,D,E,F,G,H) | Not present. | Not present. |
Unsolicited Cancel Ack (35=8, 39=4, 378=8,100,103,104,105,106,107) | The engine event time in nanoseconds. | The engine event time in milliseconds. |
End of Day Elimination Ack (35=8, 39=C) | The time of the order elimination event in nanoseconds. | The time of the order elimination event in milliseconds. |
Tag 60-TransactTime contains the time when a customer iLink message reaches the MSGW, where applicable. Otherwise, tag 60 represents the trading engine event time.
Customers may use iLink tag 60 or tag 5979 interchangeably, depending on the level of timestamp granularity needed, and can leverage them in combination with the MDP 3.0 tag 60 value.
the iLink tag 60 value will be derived from iLink tag 5979-RequestTime, but represented in the existing UTC format with millisecond precision.Â
MDP 3.0 tag 60 timestamp is sent in number of nanoseconds since the Unix epoch synced to a master clock to microsecond accuracy.
New Release Weekly Failover Testing Windows
Market Segment ID (tag 1300) | Market Segment Description | Date | Time |
---|---|---|---|
54 | CME Equity options | Tuesday and Thursday | 11:00 pm CT - MSGW failover to backup component 11:30 pm CT- MSGW failover to primary component |
70 | CME Commodity Futures | Tuesday and Thursday | 9:00 am CT - MSGW failover to backup component 9:30 am CT - MSGW failover to primary component |
84 | CBOT Treasury Futures | Tuesday and Thursday | 11:00 pm CT - MSGW failover to backup component 11:30 pm CT - MSGW failover to primary component |
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