ACI fabric typically rely on external authentication mechanisms like RADIUS, LDAP, RSA, TACACS+, etc for secure logins. However, there might be situations where the primary authentication method becomes unavailable due to issues with the external authentication server or configuration problems. The ACI fallback login mechanism provides a critical safety net in such scenarios. It allows […]
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1. Overview In Cisco ACI, a powerful feature called route leaking enables applications and services to communicate seamlessly across Virtual Routing and Forwarding (VRF) instances. This allows for efficient data flow within the network infrastructure, even when applications reside in separate VRFs for security or isolation purposes. Route leaking achieves this by sharing routing information
ACI Application Centric Deployment (ACD) and Subnet Sharing with Route Leaking Read More »
1. Overview DPP Manages bandwidth consumption on ACI fabric access interfaces, ensuring efficient use of resources. This blog uses an ACI fabric running 5.2(7f) and focuses on Data Plane Policing of l3Out interfaces. Sharing Mode: How policing is handled for multiple members within an EPG Choosing the Right Mode: The choice between shared and dedicated mode
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Cisco ACI (Application Centric Infrastructure) uses route leaking technique to allow routes to be shared between VRFs in the same tenant or in different tenants.
Route leaking reduces routing devices involved in a multiple VRF environment and improve network performance by avoiding traffic to use outside path for inter-VRF communication. But accidental route leaking can happen if manual configuration is used in a scaled environment which may increase the complexity of network operation and troubleshooting.
ACI route leaking is a powerful feature and it’s critical to understand the pros and cons during the design phase to get the most out of it based on the unique requirements of the specific deployment.
ACI Route Leaking – Shared Services (Network Centric Deployment) Read More »
Cisco ACI security architecture is based on allow-list where explicit definition of traffic flow need to be defined. Contract is a foundation for ACI security architecture where communication between EPGs|ESGs is defined. The contract relationship is between ESGs, EPGs (regular or uSig EPGs) or within EPG|ESG for intra-EPG contract.
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ACI uses L3Out to connect to external L3 domains via routing (dynamic routing protocol or static). There are multiple options and tools to optimize the L3Out for effective L3 communications between ACI and external network services. One of those is Floating L3Out.
Floating L3Out enables engineers to configure L3Out without specifying logical interfaces. Floating L3Out makes configuration, management, and troubleshooting easier. Only specific leaf nodes, called anchor leaf nodes establish routing adjacencies with external routers.
Anchor leaf node – is a leaf node that establish route peering / L3 adjacencies with the external routers. As of Cisco ACI release 6.0(1), the verified scalability number of anchor leaf nodes is 6 per L3Out.
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ACI has a feature, ‘ACI Rogue/Coop Exception List’, to mitigate the impact of rogue endpoint control and coop endpoint dampening on some legitimate frequent traffic movement during server initialization, firewall failover and others.
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Starting from release 4.2(1) ACI allows to configure an intersite L3Out on a multi-site ACI fabric. This feature enables for an endpoint in a site to send traffic to Layer 3 resources accessible via a remote L3Out connection. Before release 4.2(1) endpoints deployed in a given site can communicate with the external network domain only through a local L3Out connection.
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Designing ACI multi-site object names should not be an after thought since it has an implication during inter-site communication deployment. When contract with the right scope is applied between site-local EPGs the ACI objects are mirrored on the remote sites. The mirrored objects appear as if they are deployed in each of these sites’ controllers, while only actually being deployed in one of the sites. These mirrored objects are called “shadow” objects and they appear with the same names as the ones that were deployed directly to each site. Because of the shadow objects requirement for inter-site communication between site-local EPGs, this blogs focus on ACI multi-site object naming consideration an engineer need to be aware of.
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Policy CAM and TCAM In this article, I will discuss ACI TCAM resource utilization and optimization. In ACI policy, contract/filters are programmed in Policy CAM and Overflow TCAM (OTCAM). The policy CAM, Content Addressable Memory, is the hardware resource used by Cisco switches. Cisco ACI leaf switches use policy CAM to allow filtering of traffic
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Syslog messages A syslog in Cisco ACI can be configured to leverage system messages for troubleshooting and optimization of the ACI fabric. A fault or an event can trigger to send a log message to the console and to a logging server, if configured. A system message typically contains a subset of information about the
Configuring Syslog in Cisco ACI -UDP, TCP, TLS Read More »
This blog post focuses on ACI Role Based Access Control (RBAC) configuration. Demonstrates step by step configuration of ACI and ISE (TACACS+ provider) to achieve the use case which is to provide multi-tenant access control. Users can only access the tenants they are assigned to. Members of infra-admin will have full access to all tenant
Cisco ACI Role Based Access Control (RBAC) with ISE as TACACS+ provider Read More »
This blog post will focus on ACI contract priority. Contract is applied in a provider / consumer relationship and a leaf program a security policy (zoning rules) on TCAM (Ternary Content Addressable Memory). Zoning rule entry defines an action (permit, deny, redirect, log) based on the source EPG, the destination EPG, and filter. The source EPG and destination EPG are represented by a unique class ID ( pcTag ). Zoning rules are per VRF, defined with a unique scope and has a priority. The lower the number of the priority, the higher the priority. Zoning rule with the lower value (higher priority) win over zoning rule with a higher value (lower priority). When a traffic between EPGs match more than one zoning rules, the zoning rule priority with some higher level rules is used to decide the action applied on the traffic flow.
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The infographic video will focus on ACI contract priority. Contract is applied in a provider / consumer relationship and a leaf program a security policy (zoning rules) on TCAM (Ternary Content Addressable Memory). Zoning rule entry defines an action (permit, deny, redirect, log) based on the source EPG, the destination EPG, and filter. The source
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The ACI security architecture plays a foundational role toward Zero Trust architecture and Micro Segmentation initiatives in data center. In this blog post ACI contract structure, contract inheritance, contract labels are discussed. EPG|ESG classification, policy enforcement, and ways of deploying contracts from Macro to micro level are also covered.
When inserting a load balancer into a Cisco ACI fabric, it is important to understand the desired traffic flow, the advantage of using the ACI fabric anycast gateway, the benefit of selective traffic redirection and if DSR is required. Load balancers can be inserted into ACI fabric using the following deployment options. Policy based redirect is a feature to selectively steer traffic to service nodes. PBR with load balancers (one-arm, two-arm) plays a key role on returning traffic back to the same load balancer as the incoming traffic while keeping the client IP as a source IP.
Two Arm Load Balancer with ACI PBR destination in an L3out Read More »
An EPG with VMM domain association creates a port group on the APIC managed DVS. The name for the port group defaults to ‘Tenant_name|AP_name|EPG_name’. The name, depending on how the tenant, application profile and EPG are named, may not be simple or meaningful for the VMWare admin. The solution is custom EPG name. An EPG can optionally have a custom name with the VMM domain association. Beginning in release 4.2(3), custom EPG name is used to create a port group with a simple and meaningful name when the default ‘Tenant_name|AP_name|EPG_name’ naming doesn’t meet the need of the VMWare admin’s standard.
ACI Custom EPG Name for Simple and Meaningful Port Group Naming Read More »
When inserting a load balancer into a Cisco ACI fabric, it is important to understand the desired traffic flow, the advantage of using the ACI fabric anycast gateway, the benefit of selective traffic redirection and if DSR is required. Load balancers can be inserted into ACI fabric using the following deployment options. Policy based redirect is a feature to selectively steer traffic to service nodes. PBR with load balancers (one-arm, two-arm) plays a key role on returning traffic back to the same load balancer as the incoming traffic while keeping the client IP as a source IP.
One Arm Load Balancer with ACI PBR Destination in an L3out Read More »
When inserting a load balancer into a Cisco ACI fabric, it is important to understand the desired traffic flow, the advantage of using the ACI fabric anycast gateway, the benefit of selective traffic redirection and if DSR is required. Load balancers can be inserted into ACI fabric using the following deployment options. Policy based redirect is a feature to selectively steer traffic to service nodes. PBR with load balancers (one-arm, two-arm) plays a key role on returning traffic back to the same load balancer as the incoming traffic while keeping the client IP as a source IP.
One Arm Load Balancer with ACI Policy Based Redirect Read More »
ACI fabric supports transit routing. This feature enables a border leaf to perform bidirectional redistribution between routing domains. A transit traffic can pass from one layer 3 domain to another layer 3 domain through ACI (the ACI acting as a transit between the two layer 3 domains). A transit route is defined to import traffic through a Layer 3 outside network of an L3out where it is to be imported. A different transit route is defined to export traffic through another L3out to the destination routing domain.
The route-maps for import and export route controls are made up of prefix-list matches. Each prefix-list consists of bridge domain (BD), external subnet prefixes in the VRF and the export prefixes that need to be advertised outside. Route control policies are defined in an l3out and controlled by properties and relations associated with the l3Out. APIC uses the enforce route control property of the l3Out to enforce route control directions. The default is to enforce control on export and allow all on import. The default scope for every route is import. These are the routes and prefixes which form a prefix-based EPG…
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