doc/manuals/chapters/proxy_cache_periodic_lu.ladder

{hscale=2}
ms = MS,BSS
msc = MSC
hlr = HLR proxy
home = Home HLR

ms -> msc	Location Updating Request (Periodic)
ms () msc	Authentication,
		using the next of 5 auth tuples the MSC has stored
msc -> hlr	Update Location Request
hlr () .	Use already set up proxy path
hlr <> .	(8) proxy cache already has all information to answer
msc <- hlr	Insert Subscriber Data Request
msc -> hlr	Insert Subscriber Data Result
msc <- hlr	Update Location Result
ms <- msc	Location Updating Accept
hlr () .	(9) Verify Update Location with home HLR
|||
---		if the home HLR has no changes and accepts
hlr -> home	Update Location Request
hlr <- home	Insert Subscriber Data Request
hlr -> home	Insert Subscriber Data Result
hlr <> .	Notice identical MSISDN
hlr <- home	Update Location Result
|||
---		if the home HLR is unreachable
hlr -> home	Update Location Request
hlr <> .	no link
		or
		response timeout
hlr () .	Don't care, carry on
|||
---		if the home HLR has a modified MSISDN, and accepts
hlr -> home	Update Location Request
hlr <- home	Insert Subscriber Data Request
hlr -> home	Insert Subscriber Data Result
hlr <> .	Notice changed MSISDN
msc <- hlr	Insert Subscriber Data Request
msc -> hlr	Insert Subscriber Data Result
hlr <- home	Update Location Result
|||
---		if the home HLR rejects
hlr -> home	Update Location Request
hlr <- home	Update Location Error
msc <- hlr	Cancel Location Request
msc -> hlr	Cancel Location Result
hlr () .	Clear subscriber cache