Why downloading Apple developer content using XCode

Using Google DNS

Hydrogen:~ siuying$ dig @8.8.8.8 adcdownload.apple.com

; <<>> DiG 9.7.3-P3 <<>> adcdownload.apple.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 21486
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;adcdownload.apple.com.		IN	A

;; ANSWER SECTION:
adcdownload.apple.com.	32682	IN	CNAME	adcdownload.apple.com.akadns.net.
adcdownload.apple.com.akadns.net. 244 IN CNAME	a312.gi3.akamai.net.
a312.gi3.akamai.net.	17	IN	A	63.80.242.18
a312.gi3.akamai.net.	17	IN	A	63.80.242.17

;; Query time: 5 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Fri Jan 13 15:39:27 2012
;; MSG SIZE  rcvd: 147

Hydrogen:~ siuying$ traceroute 63.80.242.18
traceroute to 63.80.242.18 (63.80.242.18), 64 hops max, 52 byte packets
 1  192.168.88.1 (192.168.88.1)  0.781 ms  0.643 ms  0.606 ms
 2  061093241193.ctinets.com (61.93.241.193)  3.733 ms  2.433 ms  3.540 ms
 3  061093236001.ctinets.com (61.93.236.1)  1.518 ms  2.454 ms  2.322 ms
 4  014199252093.ctinets.com (14.199.252.93)  7.856 ms  15.013 ms  11.309 ms
 5  014136128050.ctinets.com (14.136.128.50)  3.722 ms  2.881 ms  2.574 ms
 6  ge-2-0-4.hkg11.ip4.tinet.net (213.254.227.49)  5.760 ms  4.382 ms  2.765 ms
 7  xe-7-2-0.sjc10.ip4.tinet.net (89.149.184.150)  180.916 ms
    xe-4-2-0.sjc10.ip4.tinet.net (89.149.186.185)  179.826 ms  180.283 ms
 8  tengige0-3-4-0.gw3.sjc7.alter.net (152.179.48.17)  174.152 ms  173.475 ms  174.536 ms
 9  a63-80-242-18.deploy.akamaitechnologies.com (63.80.242.18)  178.790 ms  173.617 ms  174.860 ms

Using HKBN Default DNS

Hydrogen:~ siuying$ dig @203.186.94.22 adcdownload.apple.com

; <<>> DiG 9.7.3-P3 <<>> @203.186.94.22 adcdownload.apple.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 3125
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;adcdownload.apple.com.		IN	A

;; ANSWER SECTION:
adcdownload.apple.com.	84146	IN	CNAME	adcdownload.apple.com.akadns.net.
adcdownload.apple.com.akadns.net. 236 IN CNAME	a312.gi3.akamai.net.
a312.gi3.akamai.net.	20	IN	A	203.186.47.155
a312.gi3.akamai.net.	20	IN	A	203.186.47.154

;; Query time: 4 msec
;; SERVER: 203.186.94.22#53(203.186.94.22)
;; WHEN: Fri Jan 13 15:48:09 2012
;; MSG SIZE  rcvd: 147


Hydrogen:~ siuying$ traceroute 203.186.47.154
traceroute to 203.186.47.154 (203.186.47.154), 64 hops max, 52 byte packets
 1  192.168.88.1 (192.168.88.1)  1.467 ms  0.608 ms  0.579 ms
 2  061093241193.ctinets.com (61.93.241.193)  14.582 ms  2.286 ms  3.543 ms
 3  061093236001.ctinets.com (61.93.236.1)  5.393 ms  4.308 ms  4.402 ms
 4  014199252093.ctinets.com (14.199.252.93)  6.545 ms  10.986 ms  11.616 ms
 5  203186047154.static.ctinets.com (203.186.47.154)  2.077 ms  2.232 ms  1.655 ms