Federal Aviation Administration Technical Operations Services AMHS/AFTN Routing in a Global Network

Topics As more AMHS systems become operational, we need to better manage the Global AMHS/AFTN routing network. These items must be considered for future AMHS connectivity : AMHS Management Domain repositories. Use of CAAS/XF Addressing scheme. Interoperability testing between all MTAs connected to the US would be the ideal scenario. However, it is mandatory to have connectivity testing between multiple MTAs that terminate at a single US MTA.

General Information-AMHS Management Domains The AMHS Address or AMHS O/R (Originator/Recipient) Address is the way in which MTAs (Message Transfer Agents) route messages. MTAs are a component of an AMHS/AFTN Gateway. An MTA is usually configured to route based on the AMHS Management Domain portion of the AMHS Address. This is comprised of the Country (C), Administrative Domain (ADMD or A), and the Private Domain (PRMD or P) attributes. Historically, the private domain attribute was reserved for the ICAO Nationality Letter assigned in Doc This guarantees : –an AFTN to AMHS address mapping for all AFTN addresses. –an AMHS route for all AFTN addresses. –a unique route for each ICAO nationality.

General Info Examples-AMHS Management Domains For example,Japan AMHS will accept messages for the following AMHS Management Domains: C=XX, A=ICAO, P=RJ -Japan C=XX, A=ICAO, P=UA - Kazakhstan C=XX, A=ICAO, P=VA - India For example, Peru AMHS might accept messages for the following AMHS Management Domains: C=XX, A=ICAO, P=SP - Peru C=XX, A=ICAO, P=SL - Bolivia C=XX, A=ICAO, P=SC – Chile For example, UK AMHS might accept messages for the following AMHS Management Domains: C=XX, A=ICAO, P=EG - UK C=XX, A=ICAO, P=ED - Germany

Interoperability Issues-AMHS Management Domains Since routing is done on AMHS Management Domains, all AMHS/AFTN gateways must use the same AMHS Management Domain repository. Japan and the US relied on a working paper, PRMD (Management Domain)_for_theUS-Japan_AMHS_service_B.doc There is an ICAO web site - t.cfm t.cfm Eurocontrol's OneSky Online website, which is accessed and managed though the AMC application

CAAS scheme : Overview An AMHS address built using the CAAS address scheme might look something like this: C=XX, A=ICAO, P=GERMANY, O=EDDD, OU1= EDZZ, CN= EDZZXXXX (=8 char AFTN Address ) C=XX, A=ICAO, P=GERMANY is the global domain identifier or AMHS Management Domain. O (Organization) attribute represents a geographical location. OU1 (Organizational Unit 1) represents a 4 character ICAO location identifier- 1 st 4 characters of the AFTN Address. CN (Common Name) represents the 8 character ICAO address.

XF scheme: Overview That same address built using the XF addressing scheme would look like this: C=XX, A=ICAO, P=GERMANY, O=AFTN, OU1= EDZZXXXX. C=XX, A=ICAO, P=GERMANY is the global domain identifier or AMHS Management Domain. O (Organization) =AFTN is a fixed field used by all AMHS/AFTN gateways. OU (Organizational Unit) represents the 8 character ICAO address.

General Information-AMHS Addressing Scheme We are using a local ATN Directory as a repository for the AMHS Management Domains and for address mapping between the AFTN and AMHS O/R addresses. We use the ATN schema defined in SARPs ATN Directory Services (DIR) – Sub volume Seven, Third Edition. We have extended the atn-AmhsMD schema to include an atn-Amhs-addr-scheme, indicating the countries scheme of choice, XF or CAAS. The address mapping is based on this attribute.

General Information-AMHS Addressing Scheme Each ICAO country may declare their choice of addressing scheme for mapping addresses within their Management Domains. An accurate representation of this should be in the same repository as the AMHS Management Domains. All AMHS/AFTN Gateways should be capable of mapping an AFTN address to either scheme.

General Info Examples-AMHS Addressing scheme Mapping an AFTN address, EDZZXXXX. If the entry for the ICAO country code, ED ( matching the first two characters of the AFTN address), were marked as CAAS addressing scheme. The AMHS address would look like this : C=XX, A=ICAO, P=GERMANY, O=EDDD, OU1= EDZZ, CN= EDZZXXXX. If the entry for the ICAO country code, ED, were marked as XF addressing scheme. The AMHS address would look like this : C=XX, A=ICAO, P=GERMANY, O=AFTN, OU1= EDZZXXXX.

Interoperability Issues-Addressing Scheme Since there are 2 ‘standard’ AMHS addressing schemes, all AMHS/AFTN Getways should be using the same repository for the address scheme of each AMHS Management domain. In our operational system in Salt Lake City, it is necessary to mark all of the AMHS Management Domains as using XF addressing. At the time of implementation, Japan was/is only capable of mapping AFTN/AMHS addresses using the XF addressing scheme. The UK has stated that they will only be using the XF addressing scheme.

Legacy Questions-Addressing scheme Why are countries declaring the use of CAAS addressing, when the AMHS/Gateway fronting for these countries only use the XF addressing scheme ? Example – ICAO country code, UU, declares CAAS. These messages transit the Japan AMHS. Japan AMHS is only capable of mapping XF addresses ??

General Information-Multiple MTAs connected to a single US MTA The AMHS/AFTN Gateway is comprised of 3 components. The MTA, the MTCU, and AFTN components. MTA routing is configured separately from the AMHS/Gateway and AFTN applications.

Examples-Multiple MTAs connected to the US MTA- Atlanta(ATN Network diagram) Routing Rules for the MTA in Atlanta, assuming UK and Peru MTAs: Peru MTA would accept messages for the following AMHS Management Domains: C=XX, A=ICAO, P=SP - Peru C=XX, A=ICAO, P=SL - Bolivia Consider a message from the UK with a recipient in Bolivia ( C=XX, A=ICAO, P=SL,O=AFTN,OU1=SLYYYFYX), and the edit position at ATL ( C=XX, A=ICAO, P=K, O=AFTN, OU1=KATLEDIT). In the current configuration, the US MTA in Atlanta accepts the message and begin it’s routing algorithm. The recipient for Bolivia would get sent to the MTA in Peru, while the US delivery would go to the AMHSGate application and further to US AFTN.

Interoperability-Multiple MTAs connected to the US MTA- Atlanta. In the previous example, the message ‘payload’ or P2 portion of the message was created by the UK MTA. The US MTA would not alter this portion of the message. The US MTA would rebuild the part of the message that the MTAs use or P1 portion of the message. In order to insure seamless operations, connectivity testing should be done between all MTAs connected to a single US MTA.

Summary These items must be considered for future AMHS connectivity: AMHS Management Domain repositories. Use of CAAS/XF Addressing scheme. Interoperability among all operational MTAs.