------ ------
/ ISP A \ / ISP B \
| AS 64500 | | AS 64510 |
\ / \ /
------- -------
| |
| |
------------ -------------
| Cust D | | Cust C |
| AS 64499 | | AS 64496 |
------------ -------------
---------------
/ \
| ISP A' |
| AS 64500 |
\ /
---------------
/ \
/ \
| |
------------ -------------
| Cust D | | Cust C |
| AS 64499 | | AS 64496 |
------------ -------------
ISP A' ISP A'
CE-A <--- PE-A <------------------- PE-B <--- CE-B
64499 New_ASN: 64500 Old_ASN: 64510 64496
New_ASN: 64500
ISP A' ISP A'
CE-A ---> PE-A -------------------> PE-B ---> CE-B
64499 New_ASN: 64500 Old_ASN: 64510 64496
New_ASN: 64500
/\ /\
\ route leak(P)/
\ propagated /
\ /
+------------+ peer +------------+
______| ISP1 (AS1) |----------->| ISP2 (AS2)|---------->
/ ------------+ prefix(P) +------------+ route leak(P)
| prefix | \ update /\ \ propagated
\ (P) / \ / \
------- prefix(P) \ / \
update \ / \
\ /route leak(P) \/
\/ /
+---------------+
| customer(AS3) |
+---------------+