37 lines
1.4 KiB
Plaintext
37 lines
1.4 KiB
Plaintext
msc {
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hscale=2;
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bsca [label="BSC-A"], i[label="MSC-I"], a[label="MSC-A"], t[label="MSC-T"], bscb[label="BSC-B"];
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i note t [label="'MSC-A,I,T' are explained in 3GPP TS 49.008 '4.3 Roles of MSC-A, MSC-I and MSC-T'"];
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i note i [label="I = Internal; the MSC that does BSSMAP to the BSC (may change to a remote MSC-B after HO)"];
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a note a [label="A = first; the MSC that has MM control BSSMAP to the BSC (never changes)"];
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t note t [label="T = transitory; the MSC that a handover is going towards (may be MSC-A for inter-BSC HO, may be a remote MSC-B)"];
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bsca => i [label="BSSMAP Handover Required"];
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i -> a [label="BSSMAP Handover Required"];
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a -> t [label="MAP Prepare Handover"];
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t => bscb [label="BSSMAP Handover Request"];
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t <= bscb [label="BSSMAP Handover Request ACK"];
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a <- t [label="MAP Prepare Handover Response"];
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i <- a [label="MAP Prepare Handover Response"];
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bsca <= i [label="BSSMAP Handover Command"];
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--- [label="MS sends RACH to new cell"];
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t <= bscb [label="BSSMAP Handover Detected"];
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a <- t [label="MAP Access Signaling Request"];
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t <= bscb [label="BSSMAP Handover Complete"];
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a <- t [label="MAP Send End Signal"];
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a abox a [label="MSC-A accepts the new BSC"];
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i note t [label="previous MSC-I gets dropped, MSC-T becomes the new MSC-I"];
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i abox i [label="discard"];
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t abox t [label="MSC-I"];
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bsca <= i [label="BSSMAP Clear Command"];
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}
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