Skip to main content

Cisco ACI - VLAN Types


Unlike the traditional Cisco switching world, where there existed only 3 VLAN types (standard, extended, private), Cisco ACI is definitely supposed to have several of them, to ensure that multitudes of Network Professionals get their brains wired!


Luckily, I came across the following ones which seem to make sense about their respective roles to have the traffic forwarding in place:


  1. VLAN ID (VlanID) - Platform independent VLAN that is locally significant to each switch. This VLAN is automatically bound to the port-group VLAN existing on the DVS. It is derived from the VLAN pool that is configured in the Fabric Access Policies.
  2. Hardware VLAN ID (HW_VlanId) - In order to switch traffic locally, most leaf switches comprise of Broadcom ASIC. This VLAN type is utilized by the Broadcom ASIC chip.
  3. Connect to Broadcom ASIC on the leaf : vsh_lc
  4. To generate the list of endpoints connected : show system internal eltmc info vlan brief

The various VLAN types are:


  • BD_CTRL_VLAN - Infrastructure VLANs.
  • BD_EXT_VLAN - These are External VLANs (eg. External Layer 3 Out).
  • FD_VLAN - These VLANs are used for EPGs. It is usually mapped to a specific EPG. On this VLAN, direct learning of endpoints from Hosts occurs.
  • BD_VLAN - Known as Bridge Domain VLAN, it can map to a single or multiple encap (FD) VLANs and VXLANs. On this VLAN no direct learning occurs.

Comments

Popular posts from this blog

Checkpoint - Exporting Objects in CSV format

Be it a Network Operations Manager, Security Architect or a Security Auditor, the people up the hierarchy always harangue the Security Engineers to compile the list of firewall objects or rules or policies or the traffic statistics and so on.. This can turn out to be quite hectic especially if there are no built in features to systematically provide the output in a "layman-readable" format. Come, Checkpoint's "Object Explorer..."  which not only provides the output in the "layman-readable" format, but also provides in-built filtering mechanisms, thereby ensuring that the Security Engineer doesn't have to rely on Google for building his scarce Microsoft Excel data filtering skills. The following screenshots will show how easy it is, with Checkpoint R80.10 to generate the firewall configuration inventory. On the SmartConsole Unified Portal, navigate to Menu >> Open Object Explorer... Select the Categories you wish to see in your output: Click o

Tejas Jain - GCP Constraints & Random Facts

1.  Google Cloud Interconnect Security Cloud Interconnect does not encrypt the connection between your on-premises network and Google's network. Cloud VPN cannot be used with Dedicated Interconnect For additional security, use application-level encryption or your own VPN 2. While using Cloud CDN, the default time-to-live (TTL) for content caching is 3600 seconds = 60 mins 3. Cloud NAT sends only the translation logs and error logs to Cloud Logging service. 4. GCP Dedicated Interconnect - On Premises network device requirements:     10-Gbps circuits, single mode fiber or 100-Gbps circuits, single mode fiber     IPv4 link local addressing     LACP, even if you are using single circuit     EBGP-4 with multi-hop     802.1Q VLANs 5. While using Cloud VPN, the recommended MTU to be configured on the peer VPN  gateway = 1460 bytes 6. Each instance must have at least one network interface. The maximum number of network instances per instance is 8, depending on the instance's machine

MITRE ATT&CK - Kerberos Vulnerabilities and Security

From the previous post, the summary of Kerberos authentication process is as below: For the initial authentication, the user’s client machine sends a request to the KDC  Authentication Service (AS) . The request includes details like the user’s username, and the date and time. All information except the username is encrypted using the hash of the user’s password. The KDC AS uses the username to look up its copy of the user’s password hash and uses it to decrypt the rest of the request. If the decryption is successful, that means the client used the correct password hash and the user has successfully authenticated. Once the user is authenticated, the KDC AS sends the user’s client a  ticket granting ticket   (TGT) . The TGT includes a unique session key and a timestamp that specifies how long that session is valid (normally 8 or 10 hours). Importantly, before sending the TGT, the KDC encrypts it using the password hash for a special account, the  KRBTGT account.  That password hash is s