远程接收器触发mLDP树的加入时的5秒延迟

简介

本文档介绍当远程接收器加入组播组以及入口PE路由器运行Cisco IOS® XR时，在多点标签分发协议(mLDP)树上转发组播流量的5秒^延迟。

背景信息

远程接收器是从源的角度跨mLDP主干的接收器。

由于Cisco Bug ID CSCvb50266，故意引入了5秒的延迟     当存在现有MVPN接收器时，5秒MLDP向本地接收器转发延迟

创建此CDETS是为了解决Cisco Bug ID CSCtg68851的问题 对于LC多路径，从默认状态切换到数据MDT不会无中断

更改

• 如果入口PE路由器在Cisco Bug ID CSCtg68851之后运行IOS®-XR版本 5秒的延迟存在。
• 如果入口PE路由器在Cisco Bug ID CSCvb50266之后运行IOS®-XR版本 ，默认情况下5秒延迟。

如果不需要，可通过隐藏的配置命令加快组播流的转发。

  

下面是一个示例。

有关测试拓扑，请参阅图1。

  

CE1是组播流232.1.1.1的源10.100.1.5。

CE2和CE1-B是组播流232.1.1.1的接收方。

测试1.远程接收器加入，无本地接收器

已启用调试：

RP/0/0/CPU0:PE1#debug mrib vrf one route
RP/0/0/CPU0:PE1#debug mfib vrf one ipv4 encap
RP/0/0/CPU0:PE1#show debug


####  debug flags set from tty 'con0_0_CPU0'  ####
ipv4 mfwd encap flag is ON with value '0x1##one'
ipv4 mrib route flag is ON with value 'one#'

入口PE路由器PE1上没有本地接收器：

RP/0/0/CPU0:PE1#sh mrib vrf one route 232.1.1.1 10.100.1.5
No matching route in MRIB route-DB
RP/0/0/CPU0:PE1#

远程接收器CE1联机：

RP/0/0/CPU0:PE1#RP/0/0/CPU0:Feb 13 10:26:33.280 : mrib[1149]:   [  6] TID: 0xe0000010 (10.100.1.5,232.1.1.1) Added RPF* EID*, #A=1, #F=1, #MDT_A=0, RPF=10.2.1.5 [Lm F* LMI* TR*] [Gi0/0/0/0 A*], Route Ver = 0x7ca
RP/0/0/CPU0:Feb 13 10:26:33.290 : ipv4_mfwd_partner[263]: Encap: encap id set  eid: 1 (10.100.1.5,232.1.1.1)
RP/0/0/CPU0:Feb 13 10:26:33.300 : mrib[1149]:   [  6] TID: 0xe0000010 (10.100.1.5,232.1.1.1) Updated RPF EID*, #A=1, #F=1, #MDT_A=0 [Lm F LMI* MA* TR], Route Ver = 0x7cc
RP/0/0/CPU0:Feb 13 10:26:33.310 : ipv4_mfwd_partner[263]: Encap: ip_mfwd_mrib_pre_process_encapid_update: encapid: 2, te_ole_cnt: 0,lsmid_ole_cnt: 1, gre_ole_cnt: 0 ti_mofrr_ole_cnt: 0 flags: 0x0
RP/0/0/CPU0:Feb 13 10:26:33.310 : ipv4_mfwd_partner[263]: Encap: [2482] Encap entry created (0xa10cb414) for eid 2 (stale N) flags 0x0
RP/0/0/CPU0:Feb 13 10:26:33.310 : ipv4_mfwd_partner[263]: Encap: [3039] RegDB entry 0xa08fd084 for LSMID 0x1d turnaround TRUE(new: Y ifh_changed N) ifhandle: b0
RP/0/0/CPU0:Feb 13 10:26:33.310 : ipv4_mfwd_partner[263]: Encap: [3533] Encap entry for eid 2 (0xa10cb414) proc done
RP/0/0/CPU0:Feb 13 10:26:33.310 : ipv4_mfwd_partner[263]: Encap: encap id update eid: 2 (10.100.1.5,232.1.1.1)

在入口PE路由器上设置encap-ID没有延迟。

这是在入口PE路由器上创建的组播转发条目：

RP/0/0/CPU0:PE1#show mrib vrf one route 232.1.1.1 10.100.1.5

IP Multicast Routing Information Base
Entry flags: L - Domain-Local Source, E - External Source to the Domain,
    C - Directly-Connected Check, S - Signal, IA - Inherit Accept,
    IF - Inherit From, D - Drop, ME - MDT Encap, EID - Encap ID,
    MD - MDT Decap, MT - MDT Threshold Crossed, MH - MDT interface handle
    CD - Conditional Decap, MPLS - MPLS Decap, EX - Extranet
    MoFE - MoFRR Enabled, MoFS - MoFRR State, MoFP - MoFRR Primary
    MoFB - MoFRR Backup, RPFID - RPF ID Set, X - VXLAN
Interface flags: F - Forward, A - Accept, IC - Internal Copy,
    NS - Negate Signal, DP - Don't Preserve, SP - Signal Present,
    II - Internal Interest, ID - Internal Disinterest, LI - Local Interest,
    LD - Local Disinterest, DI - Decapsulation Interface
    EI - Encapsulation Interface, MI - MDT Interface, LVIF - MPLS Encap,
    EX - Extranet, A2 - Secondary Accept, MT - MDT Threshold Crossed,
    MA - Data MDT Assigned, LMI - mLDP MDT Interface, TMI - P2MP-TE MDT Interface
    IRMI - IR MDT Interface

(10.100.1.5,232.1.1.1) RPF nbr: 10.2.1.5 Flags: RPF
  Up: 00:02:29
  Incoming Interface List
    GigabitEthernet0/0/0/0 Flags: A, Up: 00:02:2
  Outgoing Interface List
    Lmdtone Flags: F LMI MA TR, Up: 00:02:29

RP/0/0/CPU0:PE1#show mfib vrf one route 232.1.1.1 10.100.1.5 detail

IP Multicast Forwarding Information Base
Entry flags: C - Directly-Connected Check, S - Signal, D - Drop,
  IA - Inherit Accept, IF - Inherit From, EID - Encap ID,
  ME - MDT Encap, MD - MDT Decap, MT - MDT Threshold Crossed,
  MH - MDT interface handle, CD - Conditional Decap,
  DT - MDT Decap True, EX - Extranet, RPFID - RPF ID Set,
  MoFE - MoFRR Enabled, MoFS - MoFRR State, X - VXLAN
Interface flags: F - Forward, A - Accept, IC - Internal Copy,
  NS - Negate Signal, DP - Don't Preserve, SP - Signal Present,
  EG - Egress, EI - Encapsulation Interface, MI - MDT Interface,
  EX - Extranet, A2 - Secondary Accept
Forwarding/Replication Counts: Packets in/Packets out/Bytes out
Failure Counts: RPF / TTL / Empty Olist / Encap RL / Other

(10.100.1.5,232.1.1.1),  Flags:  EID , FMA: 0x10000 ,
  Up: 00:02:48
  Last Used: 00:00:01
  SW Forwarding Counts: 168/168/16800
  SW Replication Counts: 168/0/0
  SW Failure Counts: 0/0/0/0/0
  Route ver: 0x7d0
  MVPN Info :-
    Associated Table ID : 0xe0000000
    MDT Handle: 0x0, MDT Probe:Y [Y], Rate:Y, Acc:Y
    MDT SW Ingress Encap V4/V6, Egress decap: 0 / 0, 0
    Encap ID: 2, RPF ID: 0
    Local Receiver: False, Turnaround: False
  Lmdtone Flags:  F LMI TR, Up:00:02:48
  GigabitEthernet0/0/0/0 Flags:  A, Up:00:02:48

测试2.远程接收器与本地接收器连接

入口PE PE1处有一个本地接收器：

RP/0/0/CPU0:PE1#show mrib vrf one route 232.1.1.1 10.100.1.5

  
IP Multicast Routing Information Base
Entry flags: L - Domain-Local Source, E - External Source to the Domain,
    C - Directly-Connected Check, S - Signal, IA - Inherit Accept,
    IF - Inherit From, D - Drop, ME - MDT Encap, EID - Encap ID,
    MD - MDT Decap, MT - MDT Threshold Crossed, MH - MDT interface handle
    CD - Conditional Decap, MPLS - MPLS Decap, EX - Extranet
    MoFE - MoFRR Enabled, MoFS - MoFRR State, MoFP - MoFRR Primary
    MoFB - MoFRR Backup, RPFID - RPF ID Set, X - VXLAN
Interface flags: F - Forward, A - Accept, IC - Internal Copy,
    NS - Negate Signal, DP - Don't Preserve, SP - Signal Present,
    II - Internal Interest, ID - Internal Disinterest, LI - Local Interest,
    LD - Local Disinterest, DI - Decapsulation Interface
    EI - Encapsulation Interface, MI - MDT Interface, LVIF - MPLS Encap,
    EX - Extranet, A2 - Secondary Accept, MT - MDT Threshold Crossed,
    MA - Data MDT Assigned, LMI - mLDP MDT Interface, TMI - P2MP-TE MDT Interface
    IRMI - IR MDT Interface

(10.100.1.5,232.1.1.1) RPF nbr: 10.2.1.5 Flags: RPF
  Up: 00:57:15
  Incoming Interface List
    GigabitEthernet0/0/0/0 Flags: A, Up: 00:57:15
  Outgoing Interface List
    GigabitEthernet0/0/0/2 Flags: F NS, Up: 00:57:15

已启用调试：

RP/0/0/CPU0:PE1#debug mrib vrf one route
RP/0/0/CPU0:PE1#debug mfib vrf one ipv4 encap

RP/0/0/CPU0:PE1#show debug 

####  debug flags set from tty 'con0_0_CPU0'  ####
ipv4 mfwd encap flag is ON with value '0x1##one'
ipv4 mrib route flag is ON with value 'one#'

RP/0/0/CPU0:PE1#show mfib vrf one route 232.1.1.1 10.100.1.5 detail

IP Multicast Forwarding Information Base
Entry flags: C - Directly-Connected Check, S - Signal, D - Drop,
  IA - Inherit Accept, IF - Inherit From, EID - Encap ID,
  ME - MDT Encap, MD - MDT Decap, MT - MDT Threshold Crossed,
  MH - MDT interface handle, CD - Conditional Decap,
  DT - MDT Decap True, EX - Extranet, RPFID - RPF ID Set,
  MoFE - MoFRR Enabled, MoFS - MoFRR State, X - VXLAN
Interface flags: F - Forward, A - Accept, IC - Internal Copy,
  NS - Negate Signal, DP - Don't Preserve, SP - Signal Present,
  EG - Egress, EI - Encapsulation Interface, MI - MDT Interface,
  EX - Extranet, A2 - Secondary Accept
Forwarding/Replication Counts: Packets in/Packets out/Bytes out
Failure Counts: RPF / TTL / Empty Olist / Encap RL / Other

(10.100.1.5,232.1.1.1),  Flags:  , FMA: 0x10001 ,
  Up: 00:59:35
  Last Used: 00:00:01
  SW Forwarding Counts: 3566/3566/356600
  SW Replication Counts: 3566/3566/356600
  SW Failure Counts: 0/0/0/0/0
  Route ver: 0x3410
  MVPN Info :-
    MDT Handle: 0x0, MDT Probe:N [N], Rate:Y, Acc:Y
    MDT SW Ingress Encap V4/V6, Egress decap: 0 / 0, 0
    EG count: 1
    Encap ID: 0, RPF ID: 0
    Local Receiver: True, Turnaround: False
  GigabitEthernet0/0/0/0 Flags:  A, Up:00:59:35
  GigabitEthernet0/0/0/2 Flags:  NS EG, Up:00:59:35

encap-ID为0，因为还没有远程接收器。

CE2，远程接收器联机：

RP/0/0/CPU0:PE1#RP/0/0/CPU0:Feb 13 09:13:34.390 : mrib[1149]:   [  6] TID: 0xe0000010 (10.100.1.5,232.1.1.1) Updated RPF EID*, #A=1, #F=2, #MDT_A=0 [Lm F* LMI* TR*], Route Ver = 0x3412
RP/0/0/CPU0:Feb 13 09:13:34.390 : mrib[1149]:   [ 22] Redistributed
RP/0/0/CPU0:Feb 13 09:13:34.390 : ipv4_mfwd_partner[263]: Encap: ip_mfwd_mrib_pre_process_encapid_update: encapid: 6, te_ole_cnt: 0,lsmid_ole_cnt: 1, gre_ole_cnt: 0 ti_mofrr_ole_cnt: 0 flags: 0x1
RP/0/0/CPU0:Feb 13 09:13:34.390 : ipv4_mfwd_partner[263]: Encap: [2482] Encap entry created (0xa08fd9d0) for eid 6 (stale N) flags 0x1
RP/0/0/CPU0:Feb 13 09:13:34.390 : ipv4_mfwd_partner[263]: Encap: [3039] RegDB entry 0xa10b5404 for LSMID 0x1 turnaround TRUE(new: N ifh_changed N) ifhandle: b0
RP/0/0/CPU0:Feb 13 09:13:34.390 : ipv4_mfwd_partner[263]: Encap: [3533] Encap entry for eid 6 (0xa08fd9d0) proc done
RP/0/0/CPU0:Feb 13 09:13:34.410 : mrib[1149]:   [  6] TID: 0xe0000010 (10.100.1.5,232.1.1.1) Updated RPF EID*, #A=1, #F=2, #MDT_A=0 [Lm F LMI* MA* TR], Route Ver = 0x3414
RP/0/0/CPU0:Feb 13 09:13:34.410 : mrib[1149]:   [  6] TID: 0xe0000010 (10.100.1.5,232.1.1.1) Updated RPF EID, #A=1, #F=2, #MDT_A=0 [Lm F LMI* MA TR], Route Ver = 0x3415
RP/0/0/CPU0:Feb 13 09:13:34.410 : ipv4_mfwd_partner[263]: Encap: ip_mfwd_mrib_pre_process_encapid_update: encapid: 7, te_ole_cnt: 0,lsmid_ole_cnt: 1, gre_ole_cnt: 0 ti_mofrr_ole_cnt: 0 flags: 0x1
RP/0/0/CPU0:Feb 13 09:13:34.410 : ipv4_mfwd_partner[263]: Encap: [2482] Encap entry created (0xa08fd8a8) for eid 7 (stale N) flags 0x1
RP/0/0/CPU0:Feb 13 09:13:34.410 : ipv4_mfwd_partner[263]: Encap: [3039] RegDB entry 0xa08fd824 for LSMID 0x1c turnaround TRUE(new: Y ifh_changed N) ifhandle: b0
RP/0/0/CPU0:Feb 13 09:13:34.410 : ipv4_mfwd_partner[263]: Encap: [3533] Encap entry for eid 7 (0xa08fd8a8) proc done
RP/0/0/CPU0:Feb 13 09:13:34.500 : mrib[1149]:   [  6] TID: 0xe0000010 (10.100.1.5,232.1.1.1) Updated RPF EID, #A=1, #F=2, #MDT_A=0 [Lm F LMI* MA TR], Route Ver = 0x3416
RP/0/0/CPU0:Feb 13 09:13:34.620 : mrib[1149]:   [ 22] Redistributed
RP/0/0/CPU0:Feb 13 09:13:34.620 : mrib[1149]:   [  6] TID: 0xe0000010 (10.100.1.5,232.1.1.1) Updated RPF EID, #A=1, #F=2, #MDT_A=0 [Lm F LMI* MA TR], Route Ver = 0x3417
RP/0/0/CPU0:Feb 13 09:13:34.620 : ipv4_mfwd_partner[263]: Encap: ip_mfwd_mrib_pre_process_encapid_update: encapid: 7, te_ole_cnt: 0,lsmid_ole_cnt: 1, gre_ole_cnt: 0 ti_mofrr_ole_cnt: 0 flags: 0x1
RP/0/0/CPU0:Feb 13 09:13:34.620 : ipv4_mfwd_partner[263]: Encap: [2482] Encap entry existing (0xa08fd8a8) for eid 7 (stale N) flags 0x1
RP/0/0/CPU0:Feb 13 09:13:34.620 : ipv4_mfwd_partner[263]: Encap: [3533] Encap entry for eid 7 (0xa08fd8a8) proc done
RP/0/0/CPU0:Feb 13 09:13:39.570 : ipv4_mfwd_partner[263]: Encap: encap id set  eid: 7 (10.100.1.5,232.1.1.1)

encap-ID设置为7，即在encap-ID创建后5秒，并且组播路由信息库(MRIB)使用传出接口列表(OIL)中的虚拟路由和转发(VRF)的标记MDT(LMDT)接口进行更新。

RP/0/0/CPU0:PE1#show mrib vrf one route 232.1.1.1 10.100.1.5

IP Multicast Routing Information Base
Entry flags: L - Domain-Local Source, E - External Source to the Domain,
    C - Directly-Connected Check, S - Signal, IA - Inherit Accept,
    IF - Inherit From, D - Drop, ME - MDT Encap, EID - Encap ID,
    MD - MDT Decap, MT - MDT Threshold Crossed, MH - MDT interface handle
    CD - Conditional Decap, MPLS - MPLS Decap, EX - Extranet
    MoFE - MoFRR Enabled, MoFS - MoFRR State, MoFP - MoFRR Primary
    MoFB - MoFRR Backup, RPFID - RPF ID Set, X - VXLAN
Interface flags: F - Forward, A - Accept, IC - Internal Copy,
    NS - Negate Signal, DP - Don't Preserve, SP - Signal Present,
    II - Internal Interest, ID - Internal Disinterest, LI - Local Interest,
    LD - Local Disinterest, DI - Decapsulation Interface
    EI - Encapsulation Interface, MI - MDT Interface, LVIF - MPLS Encap,
    EX - Extranet, A2 - Secondary Accept, MT - MDT Threshold Crossed,
    MA - Data MDT Assigned, LMI - mLDP MDT Interface, TMI - P2MP-TE MDT Interface
    IRMI - IR MDT Interface

(10.100.1.5,232.1.1.1) RPF nbr: 10.2.1.5 Flags: RPF
  Up: 01:04:11
  Incoming Interface List
    GigabitEthernet0/0/0/0 Flags: A, Up: 01:04:11
  Outgoing Interface List
    Lmdtone Flags: F LMI MA TR, Up: 00:03:33
    GigabitEthernet0/0/0/2 Flags: F NS, Up: 01:04:11

RP/0/0/CPU0:PE1#show mfib vrf one route 232.1.1.1 10.100.1.5 detail

IP Multicast Forwarding Information Base
Entry flags: C - Directly-Connected Check, S - Signal, D - Drop,
  IA - Inherit Accept, IF - Inherit From, EID - Encap ID,
  ME - MDT Encap, MD - MDT Decap, MT - MDT Threshold Crossed,
  MH - MDT interface handle, CD - Conditional Decap,
  DT - MDT Decap True, EX - Extranet, RPFID - RPF ID Set,
  MoFE - MoFRR Enabled, MoFS - MoFRR State, X - VXLAN
Interface flags: F - Forward, A - Accept, IC - Internal Copy,
  NS - Negate Signal, DP - Don't Preserve, SP - Signal Present,
  EG - Egress, EI - Encapsulation Interface, MI - MDT Interface,
  EX - Extranet, A2 - Secondary Accept
Forwarding/Replication Counts: Packets in/Packets out/Bytes out
Failure Counts: RPF / TTL / Empty Olist / Encap RL / Other

(10.100.1.5,232.1.1.1),  Flags:  EID , FMA: 0x10001 ,
  Up: 01:04:25
  Last Used: 00:00:00
  SW Forwarding Counts: 3856/3856/385600
  SW Replication Counts: 3856/3856/385600
  SW Failure Counts: 0/0/0/0/0
  Route ver: 0x3417
  MVPN Info :-
    Associated Table ID : 0xe0000000
    MDT Handle: 0x0, MDT Probe:Y [Y], Rate:Y, Acc:Y
    MDT SW Ingress Encap V4/V6, Egress decap: 0 / 0, 0
    EG count: 1
    Encap ID: 7, RPF ID: 0
    Local Receiver: True, Turnaround: False
  Lmdtone Flags:  F LMI TR, Up:00:03:47
  GigabitEthernet0/0/0/0 Flags:  A, Up:01:04:25
  GigabitEthernet0/0/0/2 Flags:  NS EG, Up:01:04:25

因此，远程接收方在接收此组播流时有5秒的额外延迟。

注意：LMDT接口立即添加到MRIB中，LMDT接口也立即添加到MFIB中，并带有F标志，但未设置encap ID。

在5秒延迟后设置了MFIB中的encap ID。

在Cisco Bug ID CSCvb50266之后 ,当远程接收器加入时，编程encap-ID的延迟为5秒。这是新的默认行为。

运行命令show pim vrf <> context以验证行为：

RP/0/0/CPU0:PE1#show pim vrf one context

PIM context information for VRF one (0x12b70184)

VRF ID: 0x60000001
Table ID: 0xe0000010
Remote Table ID: 0xe0800010
MDT Default Group : 0.0.0.0
MDT Source : (10.100.1.1, Loopback0) Per-VRF
MDT Immediate Switch Not Configured
MDT handle: 0x0(Null)
Context Active, ITAL Active
Routing Enabled
Registered with MRIB
Not owner of MDT Interface
Raw socket req: T, act: T, LPTS filter req: T, act: T
UDP socket req: T, act: T, UDP vbind req: T, act: T
Reg Inj socket req: T, act: T, Reg Inj LPTS filter req: T, act: T
Mhost Default Interface : GigabitEthernet0/0/0/0 (publish pending: F)
Remote MDT Default Group : 0.0.0.0
Backup MLC virtual interface: Null
Neighbor-filter: -
MDT Neighbor-filter: -

运行此隐藏命令mdt immediate-switch以删除5秒的延迟。

RP/0/0/CPU0:PE1#conf t
RP/0/0/CPU0:PE1(config)#multicast-routing vrf one
RP/0/0/CPU0:PE1(config-mcast-one)#address-family ipv4
RP/0/0/CPU0:PE1(config-mcast-one-ipv4)#mdt immediate-switch
RP/0/0/CPU0:PE1(config-mcast-one-ipv4)#commit

注意：从7.4.1开始，该命令不再隐藏。

RP/0/0/CPU0:PE1#show pim vrf one context

PIM context information for VRF one (0x12b70184)

VRF ID: 0x60000001
Table ID: 0xe0000010
Remote Table ID: 0xe0800010
MDT Default Group : 0.0.0.0
MDT Source : (10.100.1.1, Loopback0) Per-VRF
MDT Immediate Switch Configured
MDT handle: 0x0(Null)
Context Active, ITAL Active
Routing Enabled
Registered with MRIB
Not owner of MDT Interface
Raw socket req: T, act: T, LPTS filter req: T, act: T
UDP socket req: T, act: T, UDP vbind req: T, act: T
Reg Inj socket req: T, act: T, Reg Inj LPTS filter req: T, act: T
Mhost Default Interface : GigabitEthernet0/0/0/0 (publish pending: F)
Remote MDT Default Group : 0.0.0.0
Backup MLC virtual interface: Null
Neighbor-filter: -
MDT Neighbor-filter: -

运行配置中不显示此命令：

RP/0/0/CPU0:PE1#show running-config multicast-routing vrf one

multicast-routing
 vrf one
  address-family ipv4
   interface GigabitEthernet0/0/0/0
    enable
   !
   interface GigabitEthernet0/0/0/2
    enable
   !
   mdt source Loopback0
   rate-per-route
   accounting per-prefix
   bgp auto-discovery mldp
   !
   mdt partitioned mldp ipv4 p2mp
   mdt data mldp 100 immediate-switch
  !

不支持使用immediate-switch关键字配置mdt immediate-switch和mdt data命令。
以下是此类配置的示例：

RP/0/RP0/CPU0:PE1#conf t
RP/0/RP0/CPU0:PE1(config)#multicast-routing
RP/0/RP0/CPU0:PE1(config-mcast)#vrf one
RP/0/RP0/CPU0:PE1(config-mcast-one)#address-family ipv4
RP/0/RP0/CPU0:PE1(config-mcast-one-ipv4)#mdt data mldp 100 immediate-switch
RP/0/RP0/CPU0:PE1(config-mcast-one-ipv4)#mdt immediate-switch
RP/0/RP0/CPU0:PE1(config-mcast-one-ipv4)#commit
RP/0/RP0/CPU0:PE1(config-mcast-one-ipv4)#end
RP/0/RP0/CPU0:PE1#