學(xué)習(xí)邊界網(wǎng)關(guān)協(xié)議BGP得關(guān)鍵在于如何理解和應(yīng)用協(xié)議得“屬性”，因此，本期文章將向小伙伴總結(jié)分享BGP得第七個(gè)屬性——團(tuán)體屬性（Community）。
BGP組網(wǎng)案例-團(tuán)體屬性（Community）組網(wǎng)拓?fù)鋱D組網(wǎng)拓?fù)鋱D和地址規(guī)劃如下圖所示。 備注：模擬器采用HCL 5.5.0
組網(wǎng)設(shè)備基礎(chǔ)配置組網(wǎng)設(shè)備基礎(chǔ)配置主要涉及設(shè)備命名、接口IP地址和OSPF相關(guān)配置。
#SW_1設(shè)備基礎(chǔ)配置
[H3C]sysname SW_1
[SW_1]interface LoopBack0
[SW_1-LoopBack0] ip address 10.10.0.1 255.255.255.255
[SW_1-LoopBack0]interface LoopBack1
[SW_1-LoopBack1] ip address 172.16.10.1 255.255.255.255
[SW_1-LoopBack1]quit
[SW_1]interface LoopBack2
[SW_1-LoopBack2] ip address 192.168.10.1 255.255.255.255
[SW_1-LoopBack2]quit
[SW_1]interface GigabitEthernet1/0/3
[SW_1-GigabitEthernet1/0/3] port link-mode route
[SW_1-GigabitEthernet1/0/3] ip address 10.10.13.1 255.255.255.252
[SW_1-GigabitEthernet1/0/3]quit
[SW_1]interface GigabitEthernet1/0/4
[SW_1-GigabitEthernet1/0/4] port link-mode route
[SW_1-GigabitEthernet1/0/4] ip address 10.10.14.1 255.255.255.252
[SW_1-GigabitEthernet1/0/4]quit
[SW_1]#
[SW_1]ip ttl-expires enable
[SW_1]ip unreachables enable
[SW_1]#
#SW_2設(shè)備基礎(chǔ)配置
[H3C]sysname SW_2
[SW_2]interface LoopBack0
[SW_2-LoopBack0] ip address 10.20.0.1 255.255.255.255
[SW_2-LoopBack0]quit
[SW_2]interface LoopBack1
[SW_2-LoopBack1] ip address 172.16.20.1 255.255.255.255
[SW_2-LoopBack1]quit
[SW_2]interface LoopBack2
[SW_2-LoopBack2] ip address 192.168.20.1 255.255.255.255
[SW_2-LoopBack2]quit
[SW_2]
[SW_2]interface GigabitEthernet1/0/3
[SW_2-GigabitEthernet1/0/3] port link-mode route
[SW_2-GigabitEthernet1/0/3] ip address 10.20.23.1 255.255.255.252
[SW_2-GigabitEthernet1/0/3]quit
[SW_2]interface GigabitEthernet1/0/4
[SW_2-GigabitEthernet1/0/4] port link-mode route
[SW_2-GigabitEthernet1/0/4] ip address 10.20.24.1 255.255.255.252
[SW_2-GigabitEthernet1/0/4]quit
[SW_2]ip ttl-expires enable
[SW_2]ip unreachables enable
[SW_2]#
#SW_3設(shè)備基礎(chǔ)配置
[H3C]sysname SW_3
[SW_3]interface LoopBack0
[SW_3-LoopBack0]ip address 10.30.0.3 255.255.255.255
[SW_3-LoopBack0]quit
[SW_3]interface GigabitEthernet1/0/3
[SW_3-GigabitEthernet1/0/3] port link-mode route
[SW_3-GigabitEthernet1/0/3] ip address 10.10.13.2 255.255.255.252
[SW_3-GigabitEthernet1/0/3]quit
[SW_3]interface GigabitEthernet1/0/23
[SW_3-GigabitEthernet1/0/23] port link-mode route
[SW_3-GigabitEthernet1/0/23] ip address 10.20.23.2 255.255.255.252
[SW_3-GigabitEthernet1/0/23]quit
[SW_3]#
[SW_3]interface GigabitEthernet1/0/5
[SW_3-GigabitEthernet1/0/5] port link-mode route
[SW_3-GigabitEthernet1/0/5] ip address 10.30.35.1 255.255.255.252
[SW_3-GigabitEthernet1/0/5]quit
[SW_3]ip ttl-expires enable
[SW_3]ip unreachables enable
[SW_3]#
#SW_4設(shè)備基礎(chǔ)配置
[H3C]sysname SW_4
[SW_4]interface LoopBack0
[SW_4-LoopBack0]ip address 10.30.0.4 255.255.255.255
[SW_4-LoopBack0]quit
[SW_4]interface GigabitEthernet1/0/4
[SW_4-GigabitEthernet1/0/4] port link-mode route
[SW_4-GigabitEthernet1/0/4] ip address 10.10.14.2 255.255.255.252
[SW_4-GigabitEthernet1/0/4]quit
[SW_4]interface GigabitEthernet1/0/24
[SW_4-GigabitEthernet1/0/24] port link-mode route
[SW_4-GigabitEthernet1/0/24] ip address 10.20.24.2 255.255.255.252
[SW_4-GigabitEthernet1/0/24]quit
[SW_4]interface GigabitEthernet1/0/5
[SW_4-GigabitEthernet1/0/5] port link-mode route
[SW_4-GigabitEthernet1/0/5] ip address 10.30.45.1 255.255.255.252
[SW_4-GigabitEthernet1/0/5]quit
[SW_4]ip ttl-expires enable
[SW_4]ip unreachables enable
[SW_4]#
#SW_5設(shè)備基礎(chǔ)配置
[H3C]sysname SW_5
[SW_5]interface LoopBack0
[SW_5-LoopBack0] ip address 10.30.0.5 255.255.255.255
[SW_5-LoopBack0]interface LoopBack1
[SW_5-LoopBack1] ip address 192.168.50.1 255.255.255.255
[SW_5-LoopBack1]quit
[SW_5]interface GigabitEthernet1/0/3
[SW_5-GigabitEthernet1/0/3] port link-mode route
[SW_5-GigabitEthernet1/0/3] ip address 10.30.35.2 255.255.255.252
[SW_5-GigabitEthernet1/0/3]quit
[SW_5]interface GigabitEthernet1/0/4
[SW_5-GigabitEthernet1/0/4] port link-mode route
[SW_5-GigabitEthernet1/0/4] ip address 10.30.45.2 255.255.255.252
[SW_5-GigabitEthernet1/0/4]quit
[SW_5]ip ttl-expires enable
[SW_5]ip unreachables enable
[SW_5]#
組網(wǎng)設(shè)備BGP配置#SW_1設(shè)備BGP配置
[SW_1]bgp 10
[SW_1-bgp-default] router-id 10.10.0.1
[SW_1-bgp-default] peer 10.10.13.2 as-number 30
[SW_1-bgp-default] peer 10.10.14.2 as-number 30
[SW_1-bgp-default] #
[SW_1-bgp-default] address-family ipv4 unicast
[SW_1-bgp-default-ipv4] network 172.16.10.1 255.255.255.255
[SW_1-bgp-default-ipv4] network 192.168.10.1 255.255.255.255
[SW_1-bgp-default-ipv4] peer 10.10.14.2 enable
[SW_1-bgp-default-ipv4] peer 10.10.13.2 enable
[SW_1-bgp-default-ipv4]quit
[SW_1-bgp-default]quit
[SW_1]#
#SW_2設(shè)備BGP配置
[SW_2]bgp 20
[SW_2-bgp-default] router-id 10.20.0.1
[SW_2-bgp-default] peer 10.20.23.2 as-number 30
[SW_2-bgp-default] peer 10.20.24.2 as-number 30
[SW_2-bgp-default] #
[SW_2-bgp-default] address-family ipv4 unicast
[SW_2-bgp-default-ipv4] network 172.16.20.1 255.255.255.255
[SW_2-bgp-default-ipv4] network 192.168.20.1 255.255.255.255
[SW_2-bgp-default-ipv4] peer 10.20.24.2 enable
[SW_2-bgp-default-ipv4] peer 10.20.23.2 enable
[SW_2-bgp-default-ipv4]quit
[SW_2-bgp-default]quit
[SW_2]#
#SW_3設(shè)備BGP配置
[SW_3]bgp 30
[SW_3-bgp-default] router-id 10.30.0.3
[SW_3-bgp-default] peer 10.10.13.1 as-number 10
[SW_3-bgp-default] peer 10.20.23.1 as-number 20
[SW_3-bgp-default] peer 10.30.35.2 as-number 30
[SW_3-bgp-default] #
[SW_3-bgp-default] address-family ipv4 unicast
[SW_3-bgp-default-ipv4] peer 10.10.13.1 enable
[SW_3-bgp-default-ipv4] peer 10.20.23.1 enable
[SW_3-bgp-default-ipv4] peer 10.30.35.2 enable
[SW_3-bgp-default-ipv4]peer 10.30.35.2 next-hop-local
[SW_3-bgp-default-ipv4]quit
[SW_3-bgp-default]quit
[SW_3]#
#SW_4設(shè)備BGP配置
[SW_4]bgp 30
[SW_4-bgp-default] router-id 10.30.0.4
[SW_4-bgp-default] peer 10.10.14.1 as-number 10
[SW_4-bgp-default] peer 10.20.24.1 as-number 20
[SW_4-bgp-default] peer 10.30.45.2 as-number 30
[SW_4-bgp-default] #
[SW_4-bgp-default] address-family ipv4 unicast
[SW_4-bgp-default-ipv4] peer 10.10.14.1 enable
[SW_4-bgp-default-ipv4] peer 10.20.24.1 enable
[SW_4-bgp-default-ipv4] peer 10.30.45.2 enable
[SW_4-bgp-default-ipv4]peer 10.30.45.2 next-hop-local
[SW_4-bgp-default-ipv4]quit
[SW_4-bgp-default]quit
[SW_4]#
#SW_5設(shè)備BGP配置
[SW_5]bgp 30
[SW_5-bgp-default] router-id 10.30.0.5
[SW_5-bgp-default] peer 10.30.35.1 as-number 30
[SW_5-bgp-default] peer 10.30.45.1 as-number 30
[SW_5-bgp-default] #
[SW_5-bgp-default] address-family ipv4 unicast
[SW_5-bgp-default-ipv4] network 192.168.50.1 255.255.255.255
[SW_5-bgp-default-ipv4] peer 10.30.35.1 enable
[SW_5-bgp-default-ipv4] peer 10.30.45.1 enable
[SW_5-bgp-default-ipv4]quit
[SW_5-bgp-default]quit
[SW_5]#
查看SW_5設(shè)備BGP路由表-配置團(tuán)體屬性前從SW_5設(shè)備BGP路由表可知：至目標(biāo)172.16.10.1/32、172.16.20.1/32、192.168.10.1/32和192.168.20.1/32得允許路徑，它得下一跳都是10.30.35.1，這是為何呢？
依據(jù)BGP得路由優(yōu)選規(guī)則，在其它條件相同得情況下（如本地優(yōu)先級(jí)都是100），SW_5設(shè)備最終根據(jù)“Router ”得數(shù)值大小（數(shù)值小者優(yōu)選）選擇出允許路由。
10.30.35.1——對(duì)應(yīng)SW_3設(shè)備，Router 是10.30.0.3；
10.30.45.1——對(duì)應(yīng)SW_4設(shè)備，Router 是10.30.0.4。
調(diào)試SW_1、SW_2、SW_3和SW_4設(shè)備配置SW_1設(shè)備-配置團(tuán)體屬性目得：SW_1設(shè)備向SW_3和SW_4發(fā)送BGP路由，對(duì)192.168.10.1\32得路由標(biāo)識(shí)團(tuán)體屬性號(hào)192:192, 對(duì)172.16.10.1\32得路由標(biāo)識(shí)團(tuán)體屬性號(hào)172:172
#定義地址前綴列表Com10_192
[SW_1]ip prefix-list Com10_192 index 10 permit 192.168.10.1 32
#定義地址前綴列表Com10_172
[SW_1]ip prefix-list Com10_172 index 10 permit 172.16.10.1 32
#定義路由策略 RP_Com10節(jié)點(diǎn)5，匹配Com10_192地址前綴列表得路由，賦予團(tuán)體屬性號(hào)192:192；
[SW_1]route-policy RP_Com10 permit node 5
[SW_1-route-policy-RP_Com10-5]if-match ip address prefix-list Com10_192
[SW_1-route-policy-RP_Com10-5]apply community 192:192
[SW_1-route-policy-RP_Com10-5]quit
#定義路由策略 RP_Com10節(jié)點(diǎn)10，匹配Com10_172地址前綴列表得路由，賦予團(tuán)體屬性號(hào)172:172
[SW_1]route-policy RP_Com10 permit node 10
[SW_1-route-policy-RP_Com10-10]if-match ip address prefix-list Com10_172
[SW_1-route-policy-RP_Com10-10]apply community 172:172
[SW_1-route-policy-RP_Com10-10]quit
#SW_1設(shè)備BGP相關(guān)配置
[SW_1]bgp 10
[SW_1-bgp-default] address-family ipv4 unicast
#BGP對(duì)等體調(diào)用路由策略RP_Com10，方向是export
[SW_1-bgp-default-ipv4] peer 10.10.13.2 route-policy RP_Com10 export
#配置向?qū)Φ润w發(fā)布團(tuán)體屬性，缺省情況下，BGP不會(huì)將團(tuán)體屬性發(fā)送給任何對(duì)等體。
[SW_1-bgp-default-ipv4] peer 10.10.13.2 advertise-community
[SW_1-bgp-default-ipv4]peer 10.10.14.2 route-policy RP_Com10 export
[SW_1-bgp-default-ipv4] peer 10.10.14.2 advertise-community
[SW_1-bgp-default-ipv4]quit
[SW_1-bgp-default]quit
[SW_1]
SW_2設(shè)備-配置團(tuán)體屬性目得：SW_2設(shè)備向SW_3和SW_4發(fā)送BGP路由，對(duì)192.168.20.1\32得路由標(biāo)識(shí)團(tuán)體屬性號(hào)192:192, 對(duì)172.16.20.1\32得路由標(biāo)識(shí)團(tuán)體屬性號(hào)172:172。
#定義地址前綴列表Com20_192
[SW_2]ip prefix-list Com20_192 index 10 permit 192.168.20.1 32
#定義地址前綴列表Com20_172
[SW_2]ip prefix-list Com20_172 index 10 permit 172.16.20.1 32
#定義路由策略 RP_Com20節(jié)點(diǎn)5，匹配Com20_192地址前綴列表得路由，賦予團(tuán)體屬性號(hào)192:192；
[SW_2]route-policy RP_Com20 permit node 5
[SW_2-route-policy-RP_Com20-5]if-match ip address prefix-list Com20_192
[SW_2-route-policy-RP_Com20-5] apply community 192:192
[SW_2-route-policy-RP_Com20-5]quit
#定義路由策略 RP_Com20節(jié)點(diǎn)10，匹配Com20_172地址前綴列表得路由，賦予團(tuán)體屬性號(hào)172:172
[SW_2]route-policy RP_Com20 permit node 10
[SW_2-route-policy-RP_Com20-10]if-match ip address prefix-list Com20_172
[SW_2-route-policy-RP_Com20-10] apply community 172:172
[SW_2-route-policy-RP_Com20-10]quit
#SW_2設(shè)備BGP相關(guān)配置
[SW_2]bgp 20
[SW_2-bgp-default] address-family ipv4 unicast
[SW_2-bgp-default-ipv4]peer 10.20.23.2 route-policy RP_Com20 export
[SW_2-bgp-default-ipv4]peer 10.20.23.2 advertise-community
[SW_2-bgp-default-ipv4]peer 10.20.24.2 route-policy RP_Com20 export
[SW_2-bgp-default-ipv4]peer 10.20.24.2 advertise-community
[SW_2-bgp-default-ipv4]quit
[SW_2-bgp-default]quit
[SW_2]
查看SW_3和SW_4設(shè)備收到團(tuán)體屬性得路由SW_3和SW_4設(shè)備從SW_1設(shè)備接收172.16.10.1/32得路由被標(biāo)識(shí)團(tuán)體屬性號(hào)172:172；
SW_3和SW_4設(shè)備從SW_1設(shè)備接收192.168.10.1/32得路由被標(biāo)識(shí)團(tuán)體屬性號(hào)192:192；
SW_3和SW_4設(shè)備從SW_2設(shè)備接收172.16.20.1/32得路由被標(biāo)識(shí)團(tuán)體屬性號(hào)172:172；
SW_3和SW_4設(shè)備從SW_2設(shè)備接收192.168.20.1/32得路由被標(biāo)識(shí)團(tuán)體屬性號(hào)192:192。
SW_3和SW_4設(shè)備根據(jù)標(biāo)識(shí)得團(tuán)體屬性號(hào)路由，配置路由策略，從而影響SW_5設(shè)備得BGP路由。
SW_3設(shè)備-配置根據(jù)團(tuán)體屬性得路由策略結(jié)合團(tuán)體屬性和本地優(yōu)先級(jí)屬性，在SW_3設(shè)備上配置路由策略；
#創(chuàng)建高級(jí)團(tuán)體屬性列表 Com_172，允許團(tuán)體屬性內(nèi)容172:172得路由信息通過(guò)。
[SW_3]ip community-list advanced Com_172 permit 172:172
#創(chuàng)建高級(jí)團(tuán)體屬性列表 Com_192，允許團(tuán)體屬性內(nèi)容192:192得路由信息通過(guò)。
[SW_3]ip community-list advanced Com_192 permit 192:192
#定義路由策略 R3節(jié)點(diǎn)5，匹配團(tuán)體屬性列表 Com_172得路由，賦予本地優(yōu)先級(jí)值400
[SW_3]route-policy R3 permit node 5
[SW_3-route-policy-R3-5] if-match community name Com_172
[SW_3-route-policy-R3-5] apply local-preference 400
#定義路由策略 R3節(jié)點(diǎn)10，匹配團(tuán)體屬性列表 Com_192得路由，賦予本地優(yōu)先級(jí)值200；
[SW_3-route-policy-R3-5]route-policy R3 permit node 10
[SW_3-route-policy-R3-10] if-match community name Com_192
[SW_3-route-policy-R3-10] apply local-preference 200
[SW_3-route-policy-R3-10]quit
[SW_3]
##SW_3設(shè)備BGP相關(guān)配置
[SW_3]bgp 30
[SW_3-bgp-default] address-family ipv4 unicast
#BGP對(duì)等體調(diào)用路由策略R3，方向是export
[SW_3-bgp-default-ipv4]peer 10.30.35.2 route-policy R3 export
[SW_3-bgp-default-ipv4]quit
[SW_3-bgp-default]quit
[SW_3]
SW_4設(shè)備-配置根據(jù)團(tuán)體屬性得路由策略[SW_4]ip community-list advanced Com_172 permit 172:172
[SW_4]ip community-list advanced Com_192 permit 192:192
[SW_4]route-policy R4 permit node 5
[SW_4-route-policy-R4-5] if-match community name Com_192
[SW_4-route-policy-R4-5] apply local-preference 400
[SW_4-route-policy-R4-5]#
[SW_4-route-policy-R4-5]route-policy R4 permit node 10
[SW_4-route-policy-R4-10] if-match community name Com_172
[SW_4-route-policy-R4-10] apply local-preference 200
[SW_4-route-policy-R4-10]bgp 30
[SW_4-bgp-default] address-family ipv4 unicast
[SW_4-bgp-default-ipv4] peer 10.30.45.2 route-policy R4 export
[SW_4-bgp-default-ipv4]quit
[SW_4-bgp-default]quit
[SW_4]#
查看SW_5設(shè)備BGP路由表-配置團(tuán)體屬性后從SW_5設(shè)備BGP路由表可知：
至目標(biāo)172.16.10.1/32和172.16.20.1/32得允許路徑，它們得下一跳都是10.30.35.1并且本地優(yōu)先級(jí)屬性值被賦予了400；而備選路徑，它們得下一跳都是10.30.45.1并且本地優(yōu)先級(jí)屬性值被賦予了200。
至目標(biāo)92.168.10.1/32和192.168.20.1/32得允許路徑，它們得下一跳都是10.30.45.1并且本地優(yōu)先級(jí)屬性值被賦予了400；而備選路徑，它們得下一跳都是10.30.35.1并且本地優(yōu)先級(jí)屬性值被賦予了200。
公認(rèn)團(tuán)體屬性利用公認(rèn)團(tuán)體屬性——No_Export，使SW_2無(wú)法獲取SW_1設(shè)備得BGP路由。
實(shí)現(xiàn)方式：SW_1設(shè)備配置團(tuán)體屬性得路由策略RP_Com10時(shí)，再次應(yīng)用“no-export”公認(rèn)團(tuán)體屬性。
修改SW_1得路由策略RP_Com10之前，查看SW_2設(shè)備得BGP路由表可知：設(shè)備存在至SW_1設(shè)備得BGP路由；
修改SW_1得路由策略RP_Com10策略；
[SW_1]route-policy RP_Com10 permit node 5
[SW_1-route-policy-RP_Com10-5]apply community no-export
[SW_1-route-policy-RP_Com10-5]quit
[SW_1]route-policy RP_Com10 permit node 10
[SW_1-route-policy-RP_Com10-10]apply community no-export
[SW_1-route-policy-RP_Com10-10]quit
[SW_1]
修改SW_1得路由策略RP_Com10之后，查看SW_2設(shè)備得BGP路由表可知：設(shè)備無(wú)至SW_1設(shè)備得BGP路由；
總結(jié)團(tuán)體屬性是一種“可選過(guò)渡”類型得屬性。
備注：可選過(guò)渡（Optional transitive）：在AS之間具有可傳遞性得屬性。BGP設(shè)備可以不支持此屬性，但它仍然會(huì)接收這類屬性，并傳遞給其他對(duì)等體。
團(tuán)體屬性（Community）用于標(biāo)識(shí)具有相同特征得BGP路由，使路由策略得應(yīng)用更加靈活，同時(shí)降低了維護(hù)管理得難度。
團(tuán)體屬性分為自定義團(tuán)體屬性和公認(rèn)團(tuán)體屬性。
感謝自定義得團(tuán)體屬性即是：
對(duì)192.168.10.1\32和192.168.20.1\32得路由標(biāo)識(shí)團(tuán)體屬性號(hào)192:192；
對(duì)172.16.10.1\32和172.16.20.1\32得路由標(biāo)識(shí)團(tuán)體屬性號(hào)172:172。
團(tuán)隊(duì)屬性得團(tuán)體屬性號(hào)取值有兩種形式：
1：整數(shù)形式，取值范圍是0-4294967295
2：AA:NN形式，AA和NN得取值范圍均為0-65535
公認(rèn)團(tuán)體屬性除了No_Export還有其它三種，如下圖所示；
