From e632fe891144155bfd50441ee49746ddfc138db7 Mon Sep 17 00:00:00 2001 From: TomT5454 Date: Fri, 17 May 2013 23:08:58 -0300 Subject: [PATCH] Update draft-ietf-softwire-map-deployment.xml Editorial suggestions for a few more sections. --- draft-ietf-softwire-map-deployment.xml | 116 +++++++++++++------------ 1 file changed, 60 insertions(+), 56 deletions(-) diff --git a/draft-ietf-softwire-map-deployment.xml b/draft-ietf-softwire-map-deployment.xml index df68b1b..f2814f7 100644 --- a/draft-ietf-softwire-map-deployment.xml +++ b/draft-ietf-softwire-map-deployment.xml @@ -293,7 +293,7 @@
- MAP domain connects IPv4 subnets, including home networks, enterprise + A MAP domain connects IPv4 subnets, including home networks, enterprise networks, and collective residence faclities, with the IPv4 Internet through the IPv6 routing infrastructure. @@ -326,13 +326,13 @@ Three network models are defined in : A. single ISP, single CER, internal routers; B. two ISPs, two CERs, - shared subnet; C. two ISPs, one CER, shared subnet. Model A/B is different - with model C in MAP technologies. For model A/B, one CE only need to - correspond to a BR, while in model C one CE have to correspond with multiple - BRs. illustrate a typical case, where the home - network have multiple connections to multiple providers or multiple logical - connections to the same provider. In any cases, a CE may have different + />: A. single ISP, single customer edge router (CER), internal routers; B. two ISPs, two CERs, + shared subnet; C. two ISPs, one CER, shared subnet. Models A and B are different + from model C when using MAP. For models A and B, the CE (=CER) needs to + correspond with only one BR, while in model C one CE has to correspond with multiple + BRs. illustrates a typical case, where the home + network has multiple connections to multiple providers or multiple logical + connections to the same provider. In general, a CE may have different paths towards multiple MAP border relays.
@@ -362,75 +362,79 @@
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+
- When deploying stateless MAP in operational network, a provider - should firstly do MAP domain planning based on its own network - condition. According to the definition of + When deploying stateless MAP in an operational network, a provider + should firstly do MAP domain planning based on that existing network. + According to the definition of , a MAP domain is a set of MAP CEs and BRs connected to the same virtual link. One MAP - domain shares a common BR and has the same set of BMRs, FMRs and DMR, - and it can be further divided into multiple sub-domains when multiple - IPv4 subnets are deployed in one MAP domain. All CEs in the MAP domain - are provisioned with the same set of MAP rules by MAP DHCPv6 server - . There might - be multiple BMRs in one MAP domain, and CE would pick up its own BMR by - longest prefix matching lookup. However, all CEs within the sub-domain - will have the same BMR. in which the BMR of all CEs is the same. In hub - and spoke mode, CE would use DMR as its only FMR for outbound traffic; - while in mesh mode, a longest-matching prefix lookup is done in the - IPv4 routing table and the correct FMR is chosen. + domain shares a common BR and each node within it has the same set of Basic Mapping Rules (BMRs), + Forwarding Mapping Rules (FMRs) and default mapping rule (DMR). + The MAP DHCPv6 server + provisions the common set + of MAP rules to all CEs in the MAP domain. If there are + multiple BMRs in one MAP domain, the CE will pick up its own BMR by + longest prefix matching lookup. A MAP domain can be further divided into multiple subdomains when multiple + IPv4 subnets are deployed in the domain. + All CEs within the same subdomain + will have the same BMR. In hub + and spoke mode, the CE will use the default mapping rule as its only FMR for outbound traffic, + while in mesh mode, the correct FMR is chosen by a longest-matching prefix lookup in the + IPv4 routing table and. + Basically, operator should firstly determine its own deployment - topology for MAP domain: mesh or Hub and spoke, as different - considerations for different deployment models should be applied - accordingly. Afterwards, MAP domain planning, MAP rule provision, + topology for MAP domain as described in , as different + considerations apply for different deployment models. + Next, MAP domain planning, MAP rule provision, addressing and routing, etc., for a MAP domain should be taken into - consideration. - For the scenario where one CE is corresponding to multiple MAP + consideration, as discussed in the sections following . + + For the scenario where one CE is corresponding with multiple MAP border relays, it is possible that those MAP BRs belong to different - MAP domains. The CE must pick up its own MAP rules among these - domains. It is a typical case of multihoming. The MAP rules must - have the information about BR(s) and the information about the - services types and the ISP. + MAP domains. The CE must pick up its own MAP rules and domain parameters in each + domain. This is a typical case of multihoming. The MAP rules must + have the information about BR(s) and information about the + service types and the ISP [PTT - this last bit doesn't seem to be part of MAP and should probably be dropped]. -
+
In order to do MAP domain planning, an operator should firstly - make the decision to choose Mesh or Hub and Spoke topology according - to operator's network policy. In Hub and Spoke topology, all traffic - within the same MAP domain has to go through BR which will result in - less optimized traffic; however, it would simplify the CE process + make the decision to choose mesh or hub and spoke topology according + to the operator's network policy. In the hub and spoke topology, all traffic + within the same MAP domain has to go through the BR, result in + less optimal traffic flow; however, it simplifies CE processing since there is no need to do FMR lookup for each incoming packet. - Besides, it would have enhanced management ability as BR can take + Moreover, it provides enhanced manageability as the BR can take full control of all the traffic. As a result, it is reasonable to - deploy Hub and Spoke topology for network with relatively flat + deploy hub and spoke topology for a network with a relatively flat architecture. - In mesh topology, traffic optimization can be achieved by CE to - CE direct path. It is recommended to apply mesh topology in case CE + In mesh topology, CE to CE traffic flows are optimized since they pass directly + between the two nodes. Mesh topology is recommended when CE to CE traffic is high and there are not too many MAP rules, say - less than 10 MAP rules, in the specific domain. + fewer than 10 MAP rules, in the given domain.
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- Stateless MAP has its own advantage in terms of scalability, - high-reliability, etc. As a result, it is reasonable to apply a - larger MAP domain to accommodate more subscribers with less BRs. - Moreover, a larger MAP domain would also be easier for management +
+ Stateless MAP offers advantages in terms of scalability, + high reliability, etc. As a result, it is reasonable to plan for a + larger MAP domain to accommodate more subscribers with fewer BRs. + Moreover, a larger MAP domain will also be easier for management and maintenance. However, a larger MAP domain may also result in - less optimized traffic in Hub and spoke case, where all traffic - has to go through a remote BR. Besides, it will also result in - increased number of MAP rules and highly centralized address - management, etc. It is a tradeoff to choose appropriate domain - coverage. + less optimized traffic in the hub and spoke case, where all traffic + has to go through a remote BR. In addition, it will also result in + an increased number of MAP rules and highly centralized address + management. Choosing appropriate domain + coverage requires the evaluation of tradeoffs. - Furthermore, MAP sub-domains can be divided for differentiated - service provision. Different sub-domains could be distinguished - by different Rule IPv4 prefixes. But all CEs within the same MAP - sub-domain would have the same Rule IPv4 prefix, Rule IPv6 prefix + MAP subdomains can be defined to support provision of differentiated + service. Different subdomains could be distinguished + by different Rule IPv4 prefixes. As stated previously, all CEs within the same MAP + subdomain will have the same Rule IPv4 prefix, Rule IPv6 prefix and PSID parameters.